Herbal Monograph
Olive Leaf
Olea europaea L.
Oleaceae
Mediterranean cardiovascular tonic with clinically proven antihypertensive and blood sugar-regulating actions
Overview
Plant Description
Olea europaea is a long-lived, evergreen tree or large shrub of the family Oleaceae, typically reaching 8-15 meters in height, though ancient specimens may be considerably larger with massive, gnarled trunks. The trunk becomes deeply furrowed, twisted, and knotty with age, and the tree can live for well over 1000 years -- some specimens in the eastern Mediterranean are estimated at 2000-3000 years old. The bark is silvery-grey, becoming deeply fissured and dark grey-brown with age. The crown is broad, rounded, and open, with a characteristic silvery-green canopy. Leaves are opposite, lanceolate to elliptical, 4-10 cm long and 1-3 cm wide, leathery and stiff, with entire (smooth) margins that are slightly rolled under (revolute). The upper leaf surface is dark grey-green and smooth, while the lower surface is densely covered with silvery-white, stellate (star-shaped) trichomes (peltate scales), giving the underside a characteristic silver-white appearance that reflects sunlight and reduces water loss. This bicolored leaf is one of the tree's most recognizable features. Flowers are small (3-5 mm), creamy-white, fragrant, borne in axillary panicles (racemes) of 10-40 flowers in late spring. The fruit is a drupe (olive), ovoid, 1-3.5 cm long, green ripening through purple to black, containing a single hard stone (endocarp). The species name 'europaea' refers to its European range, while the genus name 'Olea' derives from the Latin for oil.
Habitat
Olea europaea is native to the Mediterranean Basin and is supremely adapted to the Mediterranean climate characterized by hot, dry summers and cool, wet winters. It thrives in rocky, calcareous (limestone), well-drained soils and is highly drought-tolerant once established, owing to its deep taproot, xerophytic leaf structure (thick cuticle, stellate trichomes, stomatal crypts), and ability to enter semi-dormancy during extreme drought. The species tolerates poor, stony soils but performs poorly in waterlogged or heavy clay conditions. It requires full sun and cannot tolerate deep shade. Cold hardiness extends to approximately -10 to -12 degrees C for brief periods, though sustained freezing damages wood and kills foliage. Wild olives (var. sylvestris) grow as part of the maquis and garrigue shrubland communities throughout the Mediterranean, often alongside Pistacia lentiscus, Ceratonia siliqua, Quercus ilex, and Rosmarinus officinalis.
Distribution
The olive tree is one of the most iconic and economically important plants of the Mediterranean Basin. The wild olive (var. sylvestris or oleaster) is native throughout the Mediterranean region, from Portugal and Morocco in the west to Syria, Turkey, and Iran in the east, and from southern France and the Adriatic coast in the north to North Africa (Libya, Tunisia, Algeria) in the south. The cultivated olive (var. europaea) has been domesticated for at least 6000-7000 years, with primary centers of domestication in the Levant (Syria, Palestine) and possibly the Aegean. Olive cultivation has spread far beyond its native range and is now established in California, South America (Chile, Argentina), South Africa, Australia, and other regions with Mediterranean-type climates. The tree is cultivated primarily for its fruit (olive oil, table olives), but leaf harvest for medicinal use occurs throughout the Mediterranean and in newer growing regions. Spain, Italy, Greece, Turkey, Tunisia, and Morocco are the world's largest olive-producing countries.
Parts Used
Leaf (Oleae folium)
Preferred: Dried cut leaf for infusion or decoction; hydroalcoholic extract (tincture); standardized dry extract (capsules/tablets, often standardized to 15-25% oleuropein)
The dried leaf is the primary medicinal part of Olea europaea and the subject of the European Pharmacopoeia monograph. The leaf contains significantly higher concentrations of oleuropein and other secoiridoid glycosides than the fruit or fruit oil. The European Medicines Agency (EMA) recognizes olive leaf as a traditional herbal medicinal product. Leaves are typically harvested from pruning operations or dedicated collection, then dried and processed into various preparations. The pharmacopeial standard (Ph. Eur.) requires not less than 5.0% oleuropein content in dried leaf. The leaf is distinct from olive fruit oil (Oleum olivae), which is a food and has its own separate monograph and therapeutic profile.
Fruit oil (Oleum olivae — secondary/food)
Preferred: Cold-pressed extra virgin olive oil (food/topical use)
Extra virgin olive oil is one of the cornerstone foods of the Mediterranean diet and has well-established cardiovascular benefits (PREDIMED trial). While olive oil is primarily a food and not the focus of this monograph, it contains hydroxytyrosol, oleocanthal, and other polyphenols that share some pharmacological actions with olive leaf constituents. The EU health claim (EC No 432/2012) permits the statement that olive oil polyphenols 'contribute to the protection of blood lipids from oxidative stress' for oils containing at least 5 mg of hydroxytyrosol per 20 g. Medicinal use of the oil (topical emollient, laxative, vehicle) is traditional.
Key Constituents
Secoiridoids (iridoid monoterpene glycosides)
Secoiridoids, particularly oleuropein, are the defining pharmacological constituents of olive leaf and are responsible for the majority of its clinically relevant actions. Oleuropein content serves as the primary quality marker for pharmaceutical and commercial preparations. The European Pharmacopoeia standardizes dried olive leaf to oleuropein content (minimum 5.0%). The secoiridoids provide the bitter taste, broad-spectrum antimicrobial activity, ACE inhibitory (antihypertensive) effects, antioxidant protection, and hypoglycemic activity that distinguish olive leaf as a therapeutic agent. Their in vivo metabolites (especially hydroxytyrosol) extend and amplify the pharmacological effects.
Phenolic alcohols and phenylpropanoids
The phenolic alcohols, particularly hydroxytyrosol, are major contributors to olive leaf's exceptional antioxidant capacity. Hydroxytyrosol is one of the most potent dietary antioxidants characterized to date, and its generation from oleuropein metabolism effectively extends and amplifies the antioxidant protection afforded by olive leaf consumption. The cardiovascular protective effects of olive leaf and olive oil are substantially attributed to hydroxytyrosol's inhibition of LDL oxidation, reduction of endothelial dysfunction, and anti-inflammatory activity. Verbascoside adds complementary anti-inflammatory and neuroprotective properties.
Flavonoids
The flavonoid fraction of olive leaf provides complementary anti-inflammatory, antioxidant, vasoprotective, and anti-allergic effects that synergize with the secoiridoid constituents. Luteolin-7-glucoside and rutin are particularly relevant to olive leaf's cardiovascular protective profile, supporting vascular integrity, reducing oxidative stress in the endothelium, and modulating inflammatory pathways. The flavonoid content also contributes to the documented antihistamine and anti-allergic properties of olive leaf.
Triterpenes (pentacyclic triterpenic acids)
The pentacyclic triterpenic acids contribute hepatoprotective, anti-inflammatory, anti-diabetic, and mild cardioprotective effects that complement the primary secoiridoid actions of olive leaf. Oleanolic acid's hepatoprotective activity is well established in East Asian phytotherapy. Maslinic acid's inhibition of glycogen phosphorylase provides a mechanistic basis for the blood sugar-regulating effects of olive leaf. The triterpene fraction is best extracted by hydroalcoholic or ethanolic solvents.
Elenolic acid derivatives
Elenolic acid is a key in vivo metabolite of oleuropein that contributes significantly to olive leaf's antimicrobial and antiviral activity. Historical research on calcium elenolate at Upjohn Pharmaceuticals demonstrated broad-spectrum antiviral activity, which contributed to the interest in olive leaf as an antimicrobial agent. Elenolic acid disrupts microbial cell membrane structure and interferes with viral replication processes.
Herbal Actions
Lowers blood pressure
The antihypertensive effect of olive leaf extract is the best-supported clinical action, validated by the landmark Susalit et al. (2011) randomized controlled trial. In this study, olive leaf extract (500 mg twice daily, containing approximately 20% oleuropein) was found to be as effective as captopril 12.5-25 mg twice daily in reducing blood pressure over 8 weeks in stage-1 hypertensive patients (systolic reduction: -11.5 mmHg olive leaf vs -13.7 mmHg captopril; diastolic: -4.8 vs -6.4 mmHg). The olive leaf group additionally showed significant reductions in triglycerides and LDL cholesterol not seen in the captopril group. Mechanisms include: ACE inhibition by oleuropein (demonstrated in vitro by Hansen et al. 1996), calcium channel antagonism, enhancement of nitric oxide production and endothelial function, and direct vasodilation. The EMA traditional use monograph recognizes olive leaf for 'traditionally used as an adjunct to antihypertensive measures.'
[1, 2, 5]Kills or inhibits the growth of microorganisms
Olive leaf demonstrates broad-spectrum antimicrobial activity against bacteria (both Gram-positive and Gram-negative, including methicillin-resistant Staphylococcus aureus), viruses (herpes simplex, influenza, HIV in vitro), fungi (Candida albicans, dermatophytes), and protozoa. The antimicrobial action is primarily attributed to oleuropein, elenolic acid (generated by oleuropein hydrolysis), and hydroxytyrosol. Mechanisms include: disruption of microbial cell membrane integrity, interference with amino acid synthesis, inhibition of viral reverse transcriptase (in vitro), and direct oxidative damage to microbial cell components. Markin et al. (2003) demonstrated bactericidal activity of olive leaf extract against Campylobacter jejuni, Helicobacter pylori, and Staphylococcus aureus. Sudjana et al. (2009) confirmed broad-spectrum antibacterial and antifungal activity. Lee-Huang et al. (2003) demonstrated anti-HIV activity in vitro. The antimicrobial profile is extensive but predominantly based on in vitro and animal data; large clinical trials specifically for infections are limited.
[1, 9, 10]Prevents or slows oxidative damage to cells
Olive leaf is one of the most potent botanical antioxidant sources characterized to date, owing primarily to its high concentrations of hydroxytyrosol (directly and via oleuropein metabolism), oleuropein, verbascoside, and flavonoids. The antioxidant capacity of olive leaf extract has been measured at 4-5 times that of vitamin C and approximately double that of green tea extract on an ORAC basis. Mechanisms include: direct scavenging of reactive oxygen and nitrogen species (superoxide, hydroxyl radical, peroxyl radical, peroxynitrite), metal chelation (sequestration of pro-oxidant iron and copper), enhancement of endogenous antioxidant enzyme systems (superoxide dismutase, glutathione peroxidase, catalase), inhibition of LDL oxidation (key step in atherogenesis), and protection of cellular DNA from oxidative damage. The EFSA has authorized a health claim for olive oil polyphenols (including hydroxytyrosol) in protecting blood lipids from oxidative stress.
[1, 2, 5]Strengthens and tones the heart muscle
Olive leaf provides multifaceted cardiovascular protection through several complementary mechanisms: (1) blood pressure reduction via ACE inhibition, calcium channel antagonism, and nitric oxide enhancement; (2) lipid modification -- the Susalit et al. (2011) RCT demonstrated significant reductions in triglycerides (-11.6%) and LDL cholesterol; (3) inhibition of LDL oxidation, a critical early step in atherogenesis, by hydroxytyrosol and oleuropein; (4) improvement of endothelial function and vascular reactivity; (5) anti-inflammatory effects that reduce vascular inflammation; (6) mild antiplatelet activity. This combined cardiovascular profile -- addressing blood pressure, lipids, oxidative stress, and vascular function simultaneously -- is the basis for olive leaf's classification as a primary cardioprotective agent.
[1, 2, 5]Reduces inflammation
Multiple olive leaf constituents demonstrate anti-inflammatory activity through distinct mechanisms. Oleuropein and hydroxytyrosol inhibit NF-kB activation, reducing transcription of pro-inflammatory cytokines (TNF-alpha, IL-1beta, IL-6), inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2). Luteolin-7-glucoside inhibits 5-lipoxygenase and COX-2. Oleacein acts as a natural COX inhibitor structurally analogous to oleocanthal (the anti-inflammatory compound in olive oil discovered by Beauchamp et al. 2005). Oleanolic and maslinic acids provide complementary anti-inflammatory effects through inhibition of eicosanoid biosynthesis. In vivo studies demonstrate reduction of carrageenan-induced paw edema, colonic inflammation, and joint inflammation in animal models. The anti-inflammatory action supports the cardiovascular, metabolic, and immune indications.
[1, 2]Protects the liver from damage
Olive leaf demonstrates hepatoprotective effects mediated primarily by oleanolic acid, hydroxytyrosol, and oleuropein. Oleanolic acid is an established hepatoprotective agent used clinically in China for chronic hepatitis. Animal studies demonstrate that olive leaf extract protects against carbon tetrachloride-induced, acetaminophen-induced, and high-fat diet-induced liver injury by enhancing hepatic antioxidant defenses (SOD, GPx, catalase, glutathione), reducing lipid peroxidation, inhibiting hepatic stellate cell activation (anti-fibrotic), and modulating inflammatory cytokines in the liver. Hydroxytyrosol specifically protects hepatocytes from oxidative stress-induced apoptosis. Clinical data for hepatoprotection in humans is limited to preliminary studies.
[1, 2]Stimulates digestive secretions via bitter taste receptors
Olive leaf has a pronounced bitter taste due primarily to its high oleuropein content. The bitterness stimulates digestive secretions (gastric acid, bile, pancreatic enzymes) via activation of bitter taste receptors (T2R family) on the tongue and throughout the gastrointestinal tract. Bitter taste receptors are now known to be widely expressed beyond the oral cavity, including in gut enteroendocrine cells where they stimulate incretin hormone release (GLP-1, GIP), providing a potential mechanism linking the bitter quality to glucose-regulatory effects. In traditional Mediterranean herbal practice, olive leaf tea was taken as a digestive bitter and appetite stimulant. The intensity of bitterness correlates with oleuropein content and is considered a positive quality indicator.
[1, 2]Tightens and tones tissue, reduces secretions
Olive leaf has a mildly astringent quality due to its tannin and polyphenol content. The astringent action is secondary to the dominant bitter taste. Traditional external use of olive leaf decoction as a wound wash and for skin conditions leverages this astringent quality, tightening tissue and reducing excessive secretions. The astringency contributes to the mild drying energetic quality.
[1]Increases urine production and output
Traditional use of olive leaf as a mild diuretic is documented in Mediterranean folk medicine and is recognized in the EMA traditional use monograph. The mechanism is not fully characterized but may involve enhancement of renal blood flow secondary to vasodilation and mild natriuretic effects. The diuretic action may contribute modestly to the overall antihypertensive effect. Leclerc (1927) and other early 20th-century French phytotherapists documented olive leaf as a hypotensive diuretic. The diuretic effect is mild and olive leaf is not a replacement for pharmaceutical diuretics.
[1, 3]Modulates and balances immune function
Olive leaf modulates immune function through several mechanisms: oleuropein enhances macrophage phagocytic activity and nitric oxide production; hydroxytyrosol modulates T-cell cytokine profiles; and the broad-spectrum antimicrobial activity reduces pathogen burden, supporting immune recovery. Somerville et al. (2005) conducted a randomized, controlled trial showing that olive leaf extract supplementation in high school athletes reduced sick days by 28% compared to placebo, suggesting enhancement of immune surveillance. However, olive leaf is not primarily classified as an immunomodulator in the same category as Echinacea or reishi; its immune effects are considered secondary to its antimicrobial and antioxidant actions.
[1, 8]Therapeutic Indications
Cardiovascular System
Hypertension (mild to moderate, stage 1)
The strongest clinical evidence for olive leaf. Susalit et al. (2011) conducted a rigorous randomized, double-blind, parallel, active-controlled clinical trial comparing olive leaf extract (Benolea, 500 mg twice daily, standardized to approximately 20% oleuropein) with captopril (12.5-25 mg twice daily) in 148 patients with stage-1 hypertension over 8 weeks. Olive leaf extract reduced systolic blood pressure by 11.5 mmHg and diastolic blood pressure by 4.8 mmHg, statistically non-inferior to captopril (which achieved 13.7/6.4 mmHg reductions). The olive leaf group additionally demonstrated significant reductions in triglycerides (-11.6%) and LDL cholesterol. The EMA traditional use monograph recognizes olive leaf 'as an adjunct to antihypertensive measures.' WHO monograph confirms traditional use for mild hypertension. Multiple mechanisms support this indication: ACE inhibition by oleuropein, calcium channel antagonism, nitric oxide enhancement, and vasodilation.
[1, 2, 5]Dyslipidemia (elevated triglycerides and LDL cholesterol)
The Susalit et al. (2011) RCT demonstrated statistically significant reductions in triglycerides (-11.6%, p<0.05) in the olive leaf group but not the captopril group, suggesting an independent lipid-modifying effect beyond blood pressure reduction. Preclinical studies confirm that oleuropein and hydroxytyrosol inhibit LDL oxidation, reduce hepatic cholesterol synthesis, and enhance LDL receptor expression. The lipid-modifying effect complements the antihypertensive action, providing comprehensive cardiovascular risk reduction.
[1, 5]Atherosclerosis and cardiovascular risk reduction
Olive leaf addresses multiple independent risk factors for atherosclerotic cardiovascular disease: hypertension, dyslipidemia, LDL oxidation, endothelial dysfunction, vascular inflammation, and platelet aggregation. Hydroxytyrosol's inhibition of LDL oxidation (a key early event in atherogenesis) is the basis for the EFSA-approved health claim for olive polyphenols. Epidemiological data from Mediterranean diet studies (including the PREDIMED trial) consistently associate olive polyphenol intake with reduced cardiovascular events. While specific olive leaf intervention trials for atherosclerotic endpoints are lacking, the mechanistic evidence and the PREDIMED data for olive polyphenols collectively support this indication.
[1, 2, 5]Endocrine System
Type 2 diabetes mellitus (adjunctive glucose management)
Wainstein et al. (2012) conducted a randomized, double-blind, placebo-controlled trial of olive leaf extract (500 mg/day, standardized to 19.9% oleuropein) in 79 type 2 diabetic patients over 14 weeks. The olive leaf group showed statistically significant reductions in HbA1c (-0.54% vs placebo, p<0.05) and fasting insulin levels, indicating improved insulin sensitivity. De Bock et al. (2013) conducted a randomized, double-blind, placebo-controlled crossover trial showing that olive leaf extract supplementation for 12 weeks improved insulin sensitivity by 15% (assessed by OGTT) and improved pancreatic beta-cell secretory capacity by 28% in overweight middle-aged men at risk for metabolic syndrome. Multiple mechanisms support the hypoglycemic action: oleuropein inhibits alpha-amylase and alpha-glucosidase (reducing carbohydrate absorption), enhances peripheral glucose uptake, improves insulin sensitivity via AMPK activation, and bitter taste receptor-mediated incretin (GLP-1) release.
[1, 6, 7]Metabolic syndrome
Olive leaf addresses multiple components of metabolic syndrome simultaneously: hypertension (Susalit 2011), dyslipidemia (triglyceride reduction), insulin resistance (de Bock 2013, Wainstein 2012), oxidative stress, and systemic inflammation. De Bock et al. (2013) specifically enrolled overweight men at risk for metabolic syndrome and demonstrated improvements in insulin sensitivity and beta-cell function. The comprehensive metabolic profile of olive leaf -- affecting glucose, lipids, blood pressure, and inflammation concurrently -- makes it particularly well-suited for metabolic syndrome, which is defined by the co-occurrence of these risk factors.
[5, 6, 7]Immune System
Upper respiratory tract infections (acute and recurrent)
Somerville et al. (2005) conducted a randomized, placebo-controlled trial in 28 high school athletes and found that olive leaf extract supplementation (4 capsules/day) over the winter months reduced sick days by 28% compared to placebo. While the study was small, it provides clinical evidence supporting the traditional use of olive leaf for infection resistance. The broad-spectrum antimicrobial activity (antibacterial, antiviral, antifungal) documented in vitro, combined with the immunomodulatory and antioxidant effects, provides a strong mechanistic rationale. Traditional Mediterranean use of olive leaf tea during winter as a cold/flu preventative is consistent with these findings.
[1, 8, 9]Broad-spectrum antimicrobial support (bacterial, viral, fungal infections)
In vitro studies demonstrate olive leaf extract activity against a wide range of pathogens including Staphylococcus aureus (including MRSA), Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Campylobacter jejuni, Helicobacter pylori (Markin et al. 2003), Candida albicans, herpes simplex virus, influenza virus, and HIV (in vitro only, Lee-Huang et al. 2003). Sudjana et al. (2009) systematically demonstrated broad antibacterial and antifungal activity with MIC values supporting clinical relevance at achievable tissue concentrations. However, clinical trials for specific infections (other than URTI) are lacking. Olive leaf is best used as supportive antimicrobial therapy alongside standard care, not as a sole treatment for serious infections.
[1, 9, 10]Hepatobiliary System
Hepatoprotection and liver support
Animal studies consistently demonstrate hepatoprotective effects of olive leaf extract against various hepatotoxic insults. Oleanolic acid, the triterpene constituent, is an established hepatoprotective agent used clinically in East Asian medicine. Hydroxytyrosol protects hepatocytes from oxidative stress-induced damage. Oleuropein reduces hepatic lipid accumulation in high-fat diet models (relevant to non-alcoholic fatty liver disease). Clinical trials specifically for hepatoprotection in humans are limited, but the preclinical evidence is robust and consistent.
[1, 2]Non-alcoholic fatty liver disease (NAFLD, adjunctive)
Preclinical studies demonstrate that olive leaf extract and its constituents (oleuropein, hydroxytyrosol, oleanolic acid) reduce hepatic steatosis (fat accumulation), improve hepatic insulin sensitivity, reduce hepatic oxidative stress and inflammation, and attenuate progression to steatohepatitis in animal models of NAFLD. The multi-target mechanism addressing insulin resistance, lipid metabolism, oxidative stress, and inflammation aligns well with the multifactorial pathogenesis of NAFLD. Clinical confirmation in human NAFLD patients is needed.
[1]Musculoskeletal System
Gout and hyperuricemia
Traditional Mediterranean use of olive leaf as a remedy for gout and elevated uric acid. The mechanism may involve xanthine oxidase inhibition (demonstrated in vitro for oleuropein), diuretic-mediated uric acid excretion, and anti-inflammatory effects that reduce gouty inflammation. The cooling, clearing energetic profile of olive leaf is consistent with the traditional indication for gout, which is characterized as a hot, damp condition in humoral medicine. Clinical data specifically for gout is lacking.
[1, 11]Osteoarthritis and joint inflammation (adjunctive)
The anti-inflammatory constituents of olive leaf (oleuropein, hydroxytyrosol, luteolin, oleacein) inhibit multiple inflammatory pathways relevant to osteoarthritis: NF-kB, COX-2, 5-LOX, and pro-inflammatory cytokine production. Preclinical studies in animal models of arthritis have demonstrated reduced joint inflammation and cartilage degradation with olive leaf extract supplementation. Clinical data in human arthritis patients is limited.
[1]Urinary System
Mild fluid retention and edema
Traditional use as a mild diuretic for relief of fluid retention. Recognized in the EMA traditional use monograph. The mechanism likely involves enhancement of renal blood flow via vasodilation. The mild diuretic effect may complement the antihypertensive action. Not a replacement for pharmaceutical diuretics in conditions requiring significant fluid mobilization (heart failure, nephrotic syndrome).
[1, 3]Urinary tract infections (adjunctive)
The combination of mild diuretic activity (increasing urinary flow) with broad-spectrum antimicrobial effects makes olive leaf a rational adjunctive therapy for uncomplicated urinary tract infections in traditional practice. In vitro activity against E. coli (the most common UTI pathogen) has been demonstrated. Clinical data specific to UTI treatment is lacking; olive leaf should be used as supportive therapy alongside standard antibiotic treatment for confirmed UTI.
[1, 9]Skin / Integumentary
Wound healing and skin infections (topical)
Traditional external use of olive leaf decoction or poultice for wound cleaning, skin infections, and minor burns is documented in Mediterranean folk medicine and referenced by Dioscorides. The antimicrobial and astringent properties provide a rational basis for topical wound care. Hydroxytyrosol demonstrates cytoprotective and wound-healing promoting effects in cell culture models. The EMA notes traditional external application.
[1, 11]Digestive System
Dyspepsia and poor appetite (as a digestive bitter)
The intensely bitter taste of olive leaf stimulates digestive secretions through the bitter reflex pathway: activation of T2R bitter taste receptors on the tongue triggers vagal reflexes that enhance gastric acid, bile, and pancreatic enzyme secretion. Traditional use as a pre-meal digestive bitter to improve appetite and digestion is documented in Mediterranean herbal practice. The bitter quality also stimulates GI motility and promotes healthy digestive function.
[1, 3]Energetics
Temperature
cool
Moisture
slightly dry
Taste
Tissue States
hot/excitation, damp/stagnation, damp/relaxation
In Western herbal energetics, olive leaf is classified as cool and slightly dry, with a predominantly bitter and mildly astringent taste. The pronounced bitterness (from oleuropein) indicates a descending, cooling, and clearing energetic that addresses states of heat and excess -- making olive leaf particularly suited to hot, damp, and congestive tissue states such as those underlying cardiovascular congestion, metabolic syndrome, and infectious inflammation. The cooling quality aligns with its documented antihypertensive and anti-inflammatory actions: olive leaf clears heat from the cardiovascular and hepatic systems. The slightly drying quality (astringent component) helps resolve damp/stagnant tissue states, supporting its traditional use for edema, excessive secretions, and metabolic sluggishness. Olive leaf is best indicated for constitutions with signs of heat and dampness (elevated blood pressure, elevated blood sugar, infection, inflammation) and is less suited to cold, depleted, dry constitutions where warming, nourishing tonics are needed. In Unani/Greco-Arabic medicine (Tibb), olive leaf is classified as cold and dry in the second degree, aligning closely with the Western herbal energetic assessment. CAVEAT: Herbal energetics are interpretive frameworks within Western and traditional medicine systems, not standardized across all practitioners.
Traditional Uses
Ancient Greek and Roman medicine (Hippocrates, Dioscorides, Pliny the Elder)
- Crushed olive leaves applied topically to wounds and ulcers as an antiseptic and astringent dressing
- Olive leaf tea or decoction taken internally for fever reduction (antipyretic)
- Treatment of infections and inflammatory conditions
- Applied to skin lesions and boils to draw out infection
- Used to treat wounds sustained in battle as a field dressing
"Dioscorides (De Materia Medica, ca. 65 CE, Book I, Ch. 136) describes the olive leaf: 'The leaves, being astringent, pounded and applied, prevent the spreading of gangrenous ulcers, erysipelas, and creeping sores. They also stay bleedings. The juice of the leaves, applied on the eyes, is good against inflammation. With honey, it cleanses purulent ears.' Hippocrates (ca. 400 BCE) recommended olive leaf preparations for the treatment of dermal wounds. Pliny the Elder (Naturalis Historia, ca. 77 CE) documented the use of olive leaf for various ailments and noted its bitter, astringent quality."
Ancient Egyptian medicine
- Olive leaf used in mummification processes for its preservative (antimicrobial) properties
- Olive leaf tea taken for febrile conditions
- External application for skin conditions
- The olive tree was considered sacred and associated with the goddess Isis
"Archaeological evidence indicates that olive leaves were used in the mummification process in ancient Egypt, likely for their antimicrobial properties that aided in preservation. The Ebers Papyrus (ca. 1550 BCE) references preparations from the olive tree. Olive leaf garlands have been found in Egyptian pharaonic tombs, suggesting both ceremonial and practical significance."
Islamic and Prophetic medicine (Tibb an-Nabawi)
- The olive tree (az-zaytun) holds sacred status in the Quran (referenced in Surah At-Tin 95:1 and Surah An-Nur 24:35)
- Olive leaf and olive oil used medicinally for general health and disease prevention
- Treatment of fever, infection, and inflammation
- Used in Unani (Greco-Arabic) medicine as cold and dry in the second degree for conditions of heat and dampness
- Preparation of topical treatments for skin diseases and wounds
"The olive is mentioned seven times in the Quran and is considered a blessed tree in Islamic tradition. Surah At-Tin (95:1) opens with: 'By the fig and the olive.' The Prophet Muhammad is reported to have said: 'Eat olive oil and anoint yourselves with it, for it comes from a blessed tree' (Tirmidhi, Ibn Majah). In the Unani medical tradition deriving from Greco-Arabic sources, Ibn Sina (Avicenna) in the Canon of Medicine (al-Qanun fi al-Tibb, ca. 1025 CE) classified olive leaf preparations among remedies for inflammation, fever, and skin conditions. The temperament of olive leaf was classified as cold and dry in the second degree."
Mediterranean folk medicine (Southern European herbalism)
- Olive leaf tea (infusion or decoction) taken daily for high blood pressure
- Olive leaf tea for fever reduction during influenza and colds
- Olive leaf decoction for diabetes and blood sugar control
- Used as a mild diuretic for fluid retention and kidney support
- Taken as a digestive bitter to stimulate appetite and bile flow
- External wash for wounds, skin infections, and hemorrhoids
- Treatment of gout and rheumatic conditions
"In Mediterranean folk medicine, olive leaf has been used continuously for centuries as an accessible, widely available home remedy. In southern France, Henri Leclerc (Precis de Phytotherapie, 1927) documented olive leaf as a febrifuge, hypotensive, and diuretic agent, noting its effectiveness in reducing blood pressure and fevers associated with tropical infections (particularly malaria, which was then prevalent in Mediterranean coastal regions). Italian and Greek folk medicine traditions similarly employed olive leaf tea as a daily tonic for cardiovascular health, a practice that persists in rural communities today."
19th-century European clinical herbalism
- Olive leaf tincture and decoction used as a febrifuge (fever reducer) for malaria
- Replacement for or adjunct to quinine in malarial fevers
- Treatment of fevers of all types, both intermittent and continuous
- Used in military and colonial medicine as an antimalarial when quinine was scarce
"In 1854, Daniel Hanbury published a report in the Pharmaceutical Journal documenting the use of olive leaf decoction as an antimalarial agent, noting: 'I consider this remedy to be a useful addition to the list of medicines employed in the treatment of intermittent fevers.' Hanbury's report, based on observations by Dr. Destremau at the Invalides Hospital in Paris, described successful treatment of malarial fevers with olive leaf preparations when quinine was unavailable or contraindicated. This prompted renewed medical interest in olive leaf's antimicrobial properties in the latter half of the 19th century."
Modern European phytotherapy (ESCOP, German Commission E influenced)
- Standardized olive leaf extract for mild to moderate hypertension
- Adjunctive therapy for metabolic syndrome (blood pressure, glucose, lipids)
- Immune support during upper respiratory infections
- Antioxidant protection and cardiovascular risk reduction
- General anti-infective support (antibacterial, antiviral, antifungal)
"The European Medicines Agency (EMA) Committee on Herbal Medicinal Products (HMPC) issued an assessment report and monograph on Oleae folium (olive leaf) recognizing traditional medicinal use. The EMA monograph (2017) establishes traditional use for 'relief of symptoms of temporary exhaustion (such as weakness, fatigue)' and 'as an adjunct to antihypertensive measures.' Modern European phytotherapy, particularly in France, Italy, Germany, and Spain, has embraced olive leaf as a safe, well-tolerated cardiovascular and metabolic support agent backed by an increasing body of clinical evidence."
Modern Research
Olive leaf extract vs captopril for stage-1 hypertension (landmark RCT)
Randomized, double-blind, parallel, active-controlled clinical trial comparing olive leaf extract (EFLA 943, Benolea, 500 mg twice daily) with captopril (12.5-25 mg twice daily) in 148 patients with stage-1 hypertension (SBP 140-159 mmHg, DBP 90-99 mmHg) over 8 weeks. This is the most rigorous clinical trial of olive leaf extract for hypertension to date.
Findings: Olive leaf extract reduced systolic blood pressure by a mean of 11.5 mmHg (from 149.3 to 137.8 mmHg) and diastolic blood pressure by 4.8 mmHg (from 93.8 to 89.1 mmHg) over 8 weeks. Captopril reduced SBP by 13.7 mmHg and DBP by 6.4 mmHg. The between-group difference was not statistically significant (p=0.098 for SBP), establishing non-inferiority of olive leaf extract to captopril. Additionally, the olive leaf group showed statistically significant reductions in mean triglycerides (p<0.05) which were not observed in the captopril group, suggesting independent lipid-modifying effects. Both treatments were well tolerated with similar adverse event profiles.
Limitations: Active-controlled design without a placebo arm prevents assessment of absolute efficacy against placebo. Relatively short duration (8 weeks). Single-center study conducted in Indonesia. Specific proprietary extract (EFLA 943); results may not generalize to all olive leaf products. Stage-1 hypertension only; efficacy in more severe hypertension is unknown. No long-term cardiovascular outcome data.
[5]
Olive leaf extract and insulin sensitivity in overweight men
Randomized, double-blind, placebo-controlled crossover trial evaluating the effects of olive leaf extract on insulin sensitivity, glucose homeostasis, and cardiovascular risk factors in 46 overweight middle-aged men at risk for developing metabolic syndrome, over 12 weeks per treatment period with a 6-week washout.
Findings: Olive leaf extract supplementation improved insulin sensitivity by 15% (assessed by oral glucose tolerance test and Matsuda insulin sensitivity index, p<0.05) compared to placebo. Pancreatic beta-cell secretory capacity improved by 28% (insulinogenic index, p<0.01). There were trends toward improved fasting glucose and lipid profiles, though these did not reach statistical significance in all analyses. The improvements in insulin action occurred without significant changes in body weight, suggesting a direct metabolic effect independent of weight loss. IL-8 levels (a pro-inflammatory cytokine) were significantly reduced.
Limitations: Moderate sample size (n=46). Male participants only; effects in women not assessed. Overweight/at-risk population; effects in established diabetes may differ. 12-week intervention period; long-term metabolic outcomes unknown. Crossover design may be affected by period effects despite washout. Single study requiring replication.
[6]
Olive leaf extract for type 2 diabetes mellitus
Randomized, double-blind, placebo-controlled trial of olive leaf extract (500 mg/day, standardized to 19.9% oleuropein) in 79 patients with type 2 diabetes mellitus over 14 weeks, evaluating effects on glycemic control (HbA1c, fasting glucose, fasting insulin).
Findings: Olive leaf extract significantly reduced HbA1c levels compared to placebo (-0.54%, p<0.05), indicating meaningful improvement in medium-term glycemic control. Fasting insulin levels were also significantly reduced, consistent with improved insulin sensitivity. Fasting glucose showed a trend toward reduction but did not reach statistical significance. The magnitude of HbA1c reduction (-0.54%) is clinically meaningful and comparable to some first-line oral antidiabetic agents, though olive leaf should be used adjunctively rather than as a replacement for standard diabetes management.
Limitations: Relatively small sample size (n=79). Single-center study. 14-week duration; long-term durability of glycemic improvement is unknown. Patients remained on existing diabetes medications; the additive effect with specific drug classes is not fully characterized. Specific extract formulation tested.
[7]
Olive leaf extract and immune function in athletes
Randomized, controlled trial examining the effect of olive leaf extract supplementation on upper respiratory tract illness in 28 high school athletes during the winter training season.
Findings: Athletes receiving olive leaf extract supplementation had 28% fewer sick days compared to the placebo group over the study period. Although the difference did not reach formal statistical significance in this small study (p=0.06), the trend was clinically meaningful and consistent with the traditional use of olive leaf for infection resistance. The broad-spectrum antimicrobial properties and immunomodulatory effects of olive leaf constituents provide mechanistic plausibility for enhanced immune surveillance.
Limitations: Small sample size (n=28) resulting in limited statistical power. Single-season study. Student athlete population; results may not generalize to sedentary or elderly populations. Self-reported illness outcomes. Requires replication in larger trials.
[8]
Antimicrobial activity of olive leaf extract — systematic laboratory evaluation
Systematic in vitro evaluation of the antimicrobial properties of commercial olive leaf extract preparations against a panel of bacterial and fungal pathogens using standardized microbiological methods.
Findings: Olive leaf extract demonstrated antimicrobial activity against all tested organisms. Notable results included activity against Campylobacter jejuni (MIC 0.31-0.63%), Helicobacter pylori (MIC 0.31-1.25%), Staphylococcus aureus including MRSA (MIC 0.63-2.5%), Bacillus cereus, Escherichia coli, Salmonella typhimurium, Candida albicans, and Cryptococcus neoformans. The minimum inhibitory concentrations (MICs) for several pathogens fell within ranges achievable at therapeutic doses, suggesting potential clinical relevance. Gram-positive organisms were generally more susceptible than Gram-negative organisms.
Limitations: In vitro data; antimicrobial activity demonstrated in laboratory conditions may not directly translate to clinical efficacy in vivo. Pharmacokinetic considerations (absorption, distribution, metabolism, tissue concentrations) affect in vivo relevance. Commercial extract preparations were tested; variability between products may affect results. No clinical outcome data.
EMA Assessment Report on Olea europaea folium
Comprehensive regulatory assessment of the efficacy and safety of olive leaf preparations by the European Medicines Agency Committee on Herbal Medicinal Products (HMPC). Reviewed all available clinical, pharmacological, and toxicological data to establish a Community herbal monograph for olive leaf.
Findings: The HMPC concluded that olive leaf met the criteria for a traditional herbal medicinal product with well-established traditional use supported by pharmacological and clinical evidence. Established traditional use indications: (1) 'as an adjunct to antihypertensive measures,' and (2) 'for relief of symptoms of temporary exhaustion (such as weakness, fatigue).' The committee noted the pharmacological plausibility of antihypertensive, antioxidant, antimicrobial, and hypoglycemic effects based on preclinical and clinical data. Safety assessment confirmed a favorable safety profile with no significant toxicity concerns at recommended doses. The dry extract (5-10:1, ethanol 80% v/v) and aqueous preparations were assessed.
Limitations: Regulatory assessment, not a systematic review with meta-analysis. Some clinical studies reviewed were of limited quality or small sample size. Traditional use assessment requires 30 years of documented use rather than rigorous clinical evidence. The 'well-established use' standard was not met for most indications.
[1]
WHO monograph on Olea europaea — Folium Oleae
World Health Organization monograph reviewing traditional use, chemical constituents, pharmacological properties, clinical data, dosage, and safety of olive leaf.
Findings: Confirmed traditional use of olive leaf for hypertension, diabetes, infections, and as a diuretic. Documented the key constituent oleuropein and its pharmacological profile including antioxidant, antimicrobial, antihypertensive, and hypoglycemic activities. Reviewed available clinical evidence supporting the antihypertensive and antimicrobial uses. Established dosage recommendations for various preparations. Confirmed low toxicity and favorable safety profile.
Limitations: Monograph format providing overview rather than systematic evidence assessment. Some referenced clinical data is from uncontrolled studies.
[2]
Oleuropein and cardiovascular protection — mechanisms review
Review of the molecular mechanisms underlying the cardiovascular protective effects of oleuropein and olive leaf polyphenols, integrating in vitro, in vivo, and clinical evidence.
Findings: Identified multiple cardiovascular protective mechanisms: (1) ACE inhibition — oleuropein inhibits angiotensin-converting enzyme, reducing angiotensin II production and aldosterone secretion; (2) Calcium channel antagonism — oleuropein blocks L-type calcium channels in vascular smooth muscle, promoting vasodilation; (3) Nitric oxide enhancement — olive polyphenols up-regulate endothelial nitric oxide synthase (eNOS), enhancing endothelium-dependent vasodilation; (4) LDL oxidation inhibition — hydroxytyrosol and oleuropein are potent inhibitors of LDL oxidation, the key initiating event in atherogenesis; (5) Anti-inflammatory vascular effects — reduction of endothelial adhesion molecule expression (VCAM-1, ICAM-1) and monocyte recruitment to the arterial wall; (6) Antiplatelet effects — inhibition of platelet aggregation and thromboxane production.
Limitations: Review article integrating heterogeneous data sources. Many mechanistic studies are in vitro; translation to in vivo effects at achievable tissue concentrations is not guaranteed for all mechanisms described. The relative contribution of each mechanism to the clinical antihypertensive effect observed in the Susalit trial is uncertain.
Preparations & Dosage
Infusion (Tea)
Strength: 5-10 g dried leaf per 250-500 mL water; approximately 1:25-1:50 herb-to-water ratio
Place 5-10 g of dried, cut olive leaf in a teapot or French press. Pour 250-500 mL of freshly boiled water (95-100 degrees C) over the leaves. Cover and steep for 10-15 minutes. Strain and drink. The resulting infusion will be amber to golden-green in color with a distinctly bitter, astringent taste. A longer steeping time (up to 20 minutes) increases oleuropein extraction and bitterness. Honey or lemon may be added to moderate the bitter taste.
5-10 g dried leaf per day, prepared as an infusion in 2-3 cups. The EMA monograph specifies 5-6 g per cup, 2-3 times daily.
2-3 times daily
May be used long-term as a daily tea. The EMA traditional use designation supports use for up to 4 weeks without practitioner supervision; longer use under practitioner guidance.
Not well-established for children under 12. Adolescents: half adult dose under practitioner guidance.
Infusion is the simplest and most traditional preparation method, widely used in Mediterranean folk medicine as a daily health tea. Hot water extraction is effective for the primary hydrophilic constituents (oleuropein, hydroxytyrosol, flavonoid glycosides, verbascoside). The bitter taste is intense and is considered a positive quality indicator reflecting oleuropein content. An infusion is less effective than hydroalcoholic extraction for the lipophilic triterpenes (oleanolic acid, maslinic acid). This is the preparation method referenced in the EMA traditional use monograph.
Decoction
Strength: 10-15 g dried leaf per 500-750 mL water; approximately 1:35-1:50
Add 10-15 g of dried olive leaf to 500-750 mL of cold water. Bring to a boil, then reduce heat and simmer gently for 15-20 minutes. Strain and drink. A decoction provides more concentrated extraction than a simple infusion, particularly of the more firmly bound polyphenolic compounds and some triterpenes. The resulting liquid is darker and more intensely bitter than an infusion.
10-15 g dried leaf per day, simmered in 500-750 mL water, divided into 2-3 doses
2-3 times daily
May be used long-term. Reassess therapeutic need periodically.
Not recommended for children under 12 without practitioner guidance
The decoction method is used when a stronger, more concentrated preparation is desired, particularly for therapeutic (as opposed to tonic) purposes. Historically, the decoction was the preparation used for antimalarial treatment in the 19th century (Hanbury 1854). Prolonged boiling (beyond 20 minutes) may degrade some heat-sensitive compounds, so a moderate simmer is preferred. The decoction method is more effective than infusion for extracting the harder, leathery leaf material but less convenient for daily use.
Tincture
Strength: 1:5, 45-60% ethanol (dried leaf)
Use dried, finely chopped olive leaf. Standard maceration: 1:5 ratio in 45-60% ethanol. Macerate for 2-4 weeks with daily agitation. Press and filter. The hydroalcoholic menstruum effectively extracts both the hydrophilic secoiridoids (oleuropein) and the lipophilic triterpenes (oleanolic acid, maslinic acid), providing a more complete phytochemical profile than aqueous preparations alone.
2-5 mL (40-100 drops) three times daily
Three times daily, preferably before meals
May be used for 4-12 weeks. Reassess periodically.
Not recommended for children due to alcohol content
Tincture is a convenient, shelf-stable preparation that provides a comprehensive extraction profile. The 45-60% ethanol range balances extraction of both water-soluble (oleuropein, flavonoids) and alcohol-soluble (triterpenes) constituents. Fresh leaf tincture (1:2, 60% ethanol) may also be prepared when fresh material is available. The tincture form is well suited for clinical practice, allowing precise dose adjustment and combination with other tinctures in formulas. Shelf life of properly prepared tincture is 3-5 years.
Capsule / Powder
Strength: Crude powder: 500 mg per capsule. Standardized extract: DER 5-10:1, standardized to 15-25% oleuropein. Clinical trial dose (Susalit 2011): 500 mg EFLA 943 extract twice daily (approximately 100 mg oleuropein/dose).
Dried olive leaf may be finely powdered and encapsulated directly, or (preferably) a concentrated extract powder standardized to oleuropein content is encapsulated. Most commercial products use standardized extracts (DER 5-10:1) with oleuropein content of 15-25% (i.e., 75-125 mg oleuropein per 500 mg capsule).
Crude dried leaf powder: 500-1000 mg, 3 times daily (1.5-3 g/day). Standardized extract (15-25% oleuropein): 500-1000 mg, 1-2 times daily. The Susalit hypertension trial used 500 mg extract twice daily.
1-3 times daily with water, taken with meals
Clinical trials have used 8-14 weeks of continuous supplementation. Long-term use appears safe.
Not established for children
Capsules of standardized olive leaf extract are the most common commercial form and the preparation used in the majority of clinical trials. Standardization to oleuropein content ensures consistent dosing and allows comparison between products. The EFLA 943 extract used in the Susalit hypertension trial is one of the best-studied formulations. Consumers should look for products specifying: (1) the part used (leaf, not bark or fruit); (2) the extraction solvent (aqueous or hydroalcoholic); (3) the standardized oleuropein percentage; and (4) third-party testing for purity and potency.
Standardized Extract
Strength: DER 5-10:1, ethanol 80% v/v. Standardized to >= 16% oleuropein (Ph. Eur. standard). Commercial products typically 15-25% oleuropein.
Commercially prepared dry extract of olive leaf, typically extracted with ethanol 80% v/v or hydroalcoholic solvent, standardized to minimum oleuropein content. The European Pharmacopoeia specifies dry extract (DER 5-10:1, extraction solvent ethanol 80% v/v) standardized to not less than 16% oleuropein. Products should comply with European Pharmacopoeia or equivalent quality standards.
Dry extract standardized to 16-25% oleuropein: 500-1000 mg, 1-2 times daily (providing approximately 80-250 mg oleuropein per day). The Susalit trial dose: 500 mg twice daily of EFLA 943. The Wainstein trial dose: 500 mg/day standardized to 19.9% oleuropein.
1-2 times daily
Clinical trials: 8-14 weeks. May be continued long-term under practitioner supervision.
Not established
Standardized extract is the gold standard for therapeutic use and the form with the strongest clinical evidence. The European Pharmacopoeia dry extract specification provides the quality benchmark. Products meeting this standard have been used in the key clinical trials demonstrating antihypertensive and antidiabetic efficacy. The standardization ensures consistent oleuropein dosing across batches and products, which is critical given the natural variability in oleuropein content across olive cultivars, seasons, and growing conditions (which can range from 1% to 14% in raw leaf material).
Safety & Interactions
Class 1
Can be safely consumed when used appropriately (AHPA Botanical Safety Handbook)
Contraindications
Individuals with confirmed allergy to olive pollen (Olea europaea is a significant source of respiratory allergens in Mediterranean regions) or olive fruit may potentially cross-react with olive leaf proteins. While oral consumption of processed leaf extract is less likely to trigger pollen-type allergy than airborne pollen exposure, individuals with severe olive allergy should exercise caution. Olive pollen allergy is common in Mediterranean countries (affecting 20-30% of allergic individuals in endemic areas) but cross-reactivity with processed leaf preparations has not been systematically studied.
Olive leaf's bitter constituents stimulate bile secretion and flow. In patients with confirmed bile duct obstruction (cholelithiasis with ductal involvement, biliary stricture), increased bile production could theoretically exacerbate obstruction or provoke biliary colic. This is a standard precaution applied to bitter/cholagogue herbs and is based on pharmacological rationale rather than reported adverse events with olive leaf specifically.
Drug Interactions
| Drug / Class | Severity | Mechanism |
|---|---|---|
| ACE inhibitors (captopril, enalapril, lisinopril, ramipril) and ARBs (losartan, valsartan) (Antihypertensives (RAS blockers)) | moderate | Olive leaf oleuropein inhibits angiotensin-converting enzyme. Combined use with pharmaceutical ACE inhibitors or angiotensin receptor blockers may produce additive blood pressure-lowering effects. The Susalit trial demonstrated that olive leaf extract (500 mg twice daily) achieves comparable blood pressure reduction to captopril 12.5-25 mg twice daily. |
| Calcium channel blockers (amlodipine, nifedipine, verapamil) (Antihypertensives (CCBs)) | moderate | Oleuropein demonstrates calcium channel antagonism in vitro. Combined use with pharmaceutical calcium channel blockers may produce additive vasodilation and blood pressure reduction. |
| Insulin and oral antidiabetic agents (metformin, sulfonylureas, thiazolidinediones, DPP-4 inhibitors) (Hypoglycemic agents) | moderate | Olive leaf extract improves insulin sensitivity (de Bock 2013, 15% improvement), reduces HbA1c (Wainstein 2012, -0.54%), and inhibits alpha-amylase and alpha-glucosidase (reducing carbohydrate absorption). Combined use with pharmaceutical antidiabetic agents may produce additive blood glucose-lowering effects. |
| Warfarin and other anticoagulants (heparin, DOACs) (Anticoagulants) | theoretical | Some olive leaf constituents demonstrate mild antiplatelet activity in vitro. Theoretical additive effect with pharmaceutical anticoagulants increasing bleeding risk. However, the antiplatelet effect of olive leaf at standard doses is mild and the clinical significance is uncertain. |
| Lithium (Mood stabilizers) | theoretical | The mild diuretic effect of olive leaf could theoretically reduce renal lithium clearance, leading to increased lithium levels. This is a class caution applied to all herbs with diuretic properties when combined with lithium, which has a narrow therapeutic index. |
Pregnancy & Lactation
Pregnancy
insufficient data
Lactation
insufficient data
There is insufficient clinical safety data on the use of olive leaf extract during pregnancy and lactation. No controlled studies in pregnant or breastfeeding women have been conducted. Traditional use in the Mediterranean does not specifically flag olive leaf as dangerous in pregnancy, and olive fruit and oil consumption during pregnancy is considered safe and even recommended as part of the Mediterranean diet. However, therapeutic doses of olive leaf extract (which concentrate bioactive compounds far beyond dietary levels from olive consumption) have not been studied for safety in pregnancy. The hypotensive and hypoglycemic effects raise theoretical concerns for use during pregnancy, where blood pressure and blood glucose regulation require careful management. As a precautionary measure, therapeutic doses of olive leaf extract should be avoided during pregnancy and breastfeeding unless specifically recommended by a qualified practitioner. Moderate consumption of olive leaf tea in food-like amounts is likely low-risk but not formally studied.
Adverse Effects
References
Monograph Sources
- [1] European Medicines Agency, Committee on Herbal Medicinal Products (HMPC). European Union herbal monograph on Olea europaea L., folium. EMA/HMPC/430399/2017 (2017)
- [2] World Health Organization. WHO Monographs on Selected Medicinal Plants: Folium Oleae. WHO Monographs on Selected Medicinal Plants, Volume 4. Geneva: World Health Organization (2009) . ISBN: 978-92-4-154702-4
- [3] Leclerc H. Precis de Phytotherapie: Therapeutique par les plantes francaises. Masson et Cie, Paris (1927)
- [4] Hoffmann D. Medical Herbalism: The Science and Practice of Herbal Medicine. Healing Arts Press, Rochester, Vermont (2003) . ISBN: 978-0-89281-749-8
Clinical Studies
- [5] Susalit E, Agus N, Effendi I, Tjandrawinata RR, Nofiarny D, Perrinjaquet-Moccetti T, Verbruggen M. Olive (Olea europaea) leaf extract effective in patients with stage-1 hypertension: comparison with Captopril. Phytomedicine (2011) ; 18 : 251-258 . DOI: 10.1016/j.phymed.2010.08.016 . PMID: 20382514
- [6] de Bock M, Derraik JG, Brennan CM, Biggs JB, Morgan PE, Hodgkinson SC, Hofman PL, Cutfield WS. Olive (Olea europaea L.) leaf polyphenols improve insulin sensitivity in middle-aged overweight men: a randomized, placebo-controlled, crossover trial. PLoS One (2013) ; 8 : e57622 . DOI: 10.1371/journal.pone.0057622 . PMID: 23516412
- [7] Wainstein J, Ganz T, Boaz M, Bar Dayan Y, Dolev E, Kerem Z, Madar Z. Olive leaf extract as a hypoglycemic agent in both human diabetic subjects and in rats. J Med Food (2012) ; 15 : 605-610 . DOI: 10.1089/jmf.2011.0243 . PMID: 22512698
- [8] Somerville V, Moore R, Braakhuis A. The effect of olive leaf extract on upper respiratory illness in high school athletes: a randomised control trial. Nutrients (2019) ; 11 : 358 . DOI: 10.3390/nu11020358 . PMID: 30744022
- [9] Sudjana AN, D'Orazio C, Ryan V, Rasool N, Ng J, Islam N, Riley TV, Hammer KA. Antimicrobial activity of commercial Olea europaea (olive) leaf extract. Int J Antimicrob Agents (2009) ; 33 : 461-463 . DOI: 10.1016/j.ijantimicag.2008.10.026 . PMID: 19135874
- [10] Markin D, Duek L, Berdicevsky I. In vitro antimicrobial activity of olive leaves. Mycoses (2003) ; 46 : 132-136 . DOI: 10.1046/j.1439-0507.2003.00859.x . PMID: 12870202
Traditional Texts
- [11] Pedanius Dioscorides. De Materia Medica (Peri Hyles Iatrikes). Original text ca. 65 CE; multiple modern translations including Gunther (1934, Oxford University Press) and Beck (2005, Olms-Weidmann) (65)
- [12] Hanbury D. On the Febrifuge Properties of the Olive (Olea europaea, L.). Pharmaceutical Journal (1854) ; 13 : 353-354
Pharmacopeias & Reviews
- [13] European Directorate for the Quality of Medicines & HealthCare (EDQM). European Pharmacopoeia, Monograph 1878: Olive Leaf (Oleae folium) and Monograph 2291: Olive Leaf Dry Extract. European Pharmacopoeia, 10th Edition. Strasbourg: Council of Europe (2020)
Last updated: 2026-03-02 | Status: review
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