Herbal Monograph
Neem
Azadirachta indica A. Juss.
Meliaceae
The 'Village Pharmacy' -- Ayurveda's supreme bitter for skin, fever, infection, and blood purification
Overview
Plant Description
Neem is a fast-growing, medium to large evergreen or semi-deciduous tree in the mahogany family (Meliaceae), typically reaching 15-25 meters (50-80 feet) in height, occasionally to 35 meters under optimal conditions. The trunk is relatively short and straight, up to 1.2 meters in diameter, with rough, dark grey-brown bark that is deeply fissured and flaking in older specimens. The bark exudes a clear, amber gum when wounded. The crown is dense, broadly spreading, and rounded to ovate, providing excellent shade -- a key reason for its ubiquitous planting across the Indian subcontinent. Leaves are alternate, pinnately compound, 20-40 cm long, with 8-19 serrate, falcate (sickle-shaped) leaflets, each 5-10 cm long and 1-4 cm wide, with an asymmetric base. Young leaves are reddish-purple, maturing to dark green and glossy above, paler beneath. The tree is semi-deciduous, shedding leaves briefly in severe drought but remaining evergreen in moist conditions. Flowers are small (5-6 mm), white to cream, fragrant (honey-scented), borne in axillary panicles up to 25 cm long. The fruit is a smooth, olive-like drupe, 1-2 cm long, turning yellow when ripe, containing a single seed (rarely two) surrounded by a thin, sweet-tasting pulp. The seed kernel is the source of neem oil. All parts of the tree -- leaves, bark, seeds, flowers, roots, and fruit -- have been used in traditional medicine, earning it the sobriquet 'Village Pharmacy' in India. The tree is extremely long-lived, with specimens exceeding 200 years of age documented.
Habitat
Neem is native to the dry tropical and subtropical forests of the Indian subcontinent, thriving in arid and semi-arid zones with annual rainfall as low as 400 mm, though it grows best in areas receiving 400-1200 mm. It tolerates extreme heat (up to 50 degrees C) and grows in a wide range of soils including laterite, clayey, and alkaline soils, though it prefers deep, well-drained sandy loams. It does not tolerate waterlogging, frost, or prolonged temperatures below 4 degrees C. Neem colonizes degraded lands and is widely used in reforestation and desertification control programs. In its native range, it is commonly found as a roadside, village, and temple tree -- deeply integrated into the cultural and daily life of South Asian communities.
Distribution
Native to the Indian subcontinent (India, Pakistan, Bangladesh, Sri Lanka, Nepal, Myanmar), neem has been extensively introduced and naturalized across tropical and subtropical regions worldwide between latitudes 35 degrees N and 35 degrees S. It is now widely established in Sub-Saharan Africa (particularly West Africa, East Africa, and the Sahel), Southeast Asia (Thailand, Indonesia, Philippines, Cambodia), the Caribbean, Central and South America, and northern Australia. India remains the largest source of neem products, with an estimated 14-25 million neem trees. The tree was introduced to Africa in the early 20th century for shade and firewood and has since become naturalized across the continent. It is considered invasive in some regions of Australia, parts of Central America, and several Pacific islands.
Parts Used
Leaf (Nimba Patra)
Preferred: Dried leaf infusion or decoction; leaf powder (churna) in capsules; fresh leaf juice; topical paste
The most widely used and safest medicinal part. Contains nimbin, nimbidin, nimbiol, quercetin, beta-sitosterol, and lower concentrations of azadirachtin compared to seeds. Used for skin conditions, fevers, diabetes management, and as a general blood purifier in Ayurveda. The leaf is the part recommended for most internal medicinal applications due to its established safety profile when used at traditional doses.
Bark (Nimba Tvak)
Preferred: Decoction; dried bark powder; tincture
Rich in tannins, nimbidin, nimbin, and polysaccharides. The bark is traditionally used as a bitter tonic, antipyretic, and for gastrointestinal conditions. It has strong astringent and antimicrobial properties. Neem bark is official in the Indian Pharmacopoeia. Safer than seed oil for internal use but still requires appropriate dosing.
Seed oil (Neem oil, Nimba Taila)
Preferred: Cold-pressed oil for external application; diluted in carrier oil for skin application; encapsulated for controlled adult internal use under professional guidance only
Cold-pressed from the seed kernels, containing the highest concentration of azadirachtin (typically 300-2500 ppm) along with nimbin, nimbidin, salannin, and fatty acids (oleic, stearic, palmitic). Primarily used externally for skin conditions, as an insecticide/pesticide, and in hair care. CAUTION: Internal use of neem oil is controversial and potentially dangerous, especially for children. Cases of Reye-like syndrome (encephalopathy and fatty liver degeneration) have been reported in children given neem oil internally. Internal use should be strictly avoided in children and used only with extreme caution and professional guidance in adults.
Twig (Nimba Danta Kashtha / Datun)
Preferred: Fresh twig chewed as dental stick; neem twig extract in toothpaste and mouthwash formulations
Fresh neem twigs have been used as natural toothbrushes (datun) across South Asia and Africa for centuries. The twig end is chewed to fray into bristles and used to clean teeth and massage gums. Contains antimicrobial compounds that reduce oral bacteria, plaque, and gingivitis. The WHO has recognized the neem chewing stick as an effective oral hygiene tool. Clinical trials have demonstrated efficacy comparable to conventional toothbrushes in plaque reduction.
Flower (Nimba Pushpa)
Preferred: Fresh or dried flowers in decoction or as food; flower extract
Small, fragrant white flowers used in Ayurvedic and South Indian traditional medicine. Traditionally indicated for intestinal worms, anorexia, nausea, and bilious conditions. In South Indian cuisine, neem flowers are briefly blanched and used in seasonal dishes (Ugadi Pachadi in Telugu cuisine, mixed with jaggery and tamarind). Flower extracts have demonstrated antiulcer and hepatoprotective activity in animal studies.
Key Constituents
Limonoids (tetranortriterpenoids)
The limonoids are the most distinctive and pharmacologically important class of neem constituents. Over 300 structurally related limonoids have been identified from various parts of the neem tree, making it the richest known source of these compounds in the plant kingdom. Collectively, they are responsible for the insecticidal, antiparasitic, anti-inflammatory, antipyretic, antimalarial, immunomodulatory, and antimicrobial activities of neem. The limonoid profile varies significantly between plant parts: seeds contain the highest concentrations (particularly azadirachtin), bark is rich in nimbidin and nimbiol, and leaves contain a broader but lower-concentration array. The intensely bitter taste of neem is primarily due to these limonoids.
Flavonoids and phenolic compounds
The flavonoid and phenolic constituents of neem contribute to its antioxidant, anti-inflammatory, antimicrobial, and hepatoprotective activities. While individually less distinctive than the limonoids, collectively these compounds provide significant free radical scavenging capacity and synergize with the limonoids in anti-inflammatory and antimicrobial actions. The phenolic content is particularly relevant to the medicinal use of neem leaves and bark.
Phytosterols and terpenoids
Phytosterols contribute to the anti-inflammatory, immunomodulatory, and cholesterol-lowering properties of neem preparations. Beta-sitosterol is a well-studied compound with particular relevance to prostate health and cardiovascular protection.
Polysaccharides and glycoproteins
Neem polysaccharides contribute to the immunomodulating properties of leaf and bark preparations. While less extensively studied than neem limonoids, the polysaccharide fractions demonstrate significant immunostimulatory activity that may complement the anti-inflammatory effects of the limonoid constituents.
Tannins
Tannins are primarily relevant to the astringent, wound-healing, antidiarrheal, and oral health applications of neem bark and bark-containing preparations. They contribute to the antimicrobial activity of neem bark decoctions and are a major factor in the effectiveness of neem twig chewing sticks for oral hygiene.
Sulfur-containing compounds and fatty acids (seed oil)
The fatty acid and sulfur compound content of neem seed oil is primarily relevant to topical applications. The oil base delivers limonoids to the skin while the fatty acids provide emollient and anti-inflammatory effects. The organosulfur compounds contribute to insect-repellent and antimicrobial activity.
Herbal Actions
Kills or inhibits the growth of microorganisms
Neem demonstrates broad-spectrum antimicrobial activity against gram-positive bacteria (Staphylococcus aureus including MRSA, Streptococcus mutans, S. pyogenes, Bacillus subtilis), gram-negative bacteria (Escherichia coli, Salmonella typhi, Pseudomonas aeruginosa, Klebsiella pneumoniae), fungi (Candida albicans, Aspergillus niger, dermatophytes including Trichophyton, Microsporum, and Epidermophyton species), and certain viruses (dengue, coxsackievirus, HIV entry inhibition in vitro). Multiple constituents contribute: nimbidin, nimbiol, and nimbin from bark; azadirachtin, nimbin, and gedunin from seeds and leaves; gallic acid and catechins from leaves. The WHO has recognized neem-based oral hygiene products based on demonstrated antimicrobial activity against oral pathogens.
[1, 2, 3, 10]Reduces inflammation
Potent anti-inflammatory activity demonstrated across multiple in vivo and in vitro models. Nimbidin inhibits prostaglandin synthesis (COX-1 and COX-2 inhibition) and reduces inflammation in carrageenan-induced paw edema models at efficacy comparable to standard NSAIDs. Nimbin demonstrates antihistaminic activity. Azadirachtin modulates NF-kB signaling, reducing pro-inflammatory cytokine production (TNF-alpha, IL-1beta, IL-6). Neem leaf extracts have shown significant anti-inflammatory activity in adjuvant-induced arthritis models. The combined action of limonoids, flavonoids, and polysaccharides provides multi-target anti-inflammatory effects relevant to skin conditions, arthritis, fever, and gastrointestinal inflammation.
[1, 2, 3]Stimulates digestive secretions via bitter taste receptors
Neem is one of the most intensely bitter plants in the materia medica, with bitterness attributable to the high limonoid content. In Ayurveda, neem is the archetypal tikta (bitter) rasa herb, indicated for conditions of excess pitta (heat/inflammation) and kapha (dampness/congestion). The bitter quality stimulates digestive secretions (HCl, bile, pancreatic enzymes) via bitter taste receptor (T2R) activation, supports hepatobiliary function, and promotes appetite in anorexic conditions. The Ayurvedic concept of tikta rasa aligns closely with the Western herbal concept of the bitter tonic.
[1, 7, 9]Modulates and balances immune function
Neem leaf and bark polysaccharides stimulate macrophage phagocytic activity, enhance NK cell cytotoxicity, and promote lymphocyte proliferation. Aqueous neem leaf extract increased antibody titers and cell-mediated immune responses in immunized animals. Neem bark extract enhanced splenocyte proliferation and cytokine production (IFN-gamma, IL-2). Azadirachtin modulates NF-kB and MAPK signaling pathways. Importantly, neem also demonstrates anti-inflammatory and immunosuppressive effects in autoimmune and allergic models, suggesting bidirectional immunomodulation rather than simple immunostimulation. This dual activity is consistent with its Ayurvedic classification as a blood purifier (rakta shodhaka) that clears excess immune-mediated heat.
[1, 2, 3]Protects the liver from damage
Neem leaf and bark extracts demonstrate significant hepatoprotective activity in paracetamol-induced, carbon tetrachloride-induced, and thioacetamide-induced liver injury models. Mechanisms include: enhancement of hepatic antioxidant enzymes (SOD, catalase, glutathione peroxidase), reduction of lipid peroxidation (MDA), normalization of elevated liver enzymes (ALT, AST, ALP), and anti-inflammatory cytokine modulation in hepatic tissue. The flavonoids (quercetin, rutin) and limonoids (nimbolide, azadirachtin) are the primary hepatoprotective constituents. Neem flower extract also demonstrated dose-dependent hepatoprotection in animal models.
[1, 2, 3]Gradually restores proper body function and increases overall health
In Ayurveda, neem is one of the foremost rakta shodhaka (blood purifier) herbs, indicated for conditions arising from impure blood -- a concept that encompasses chronic skin diseases, systemic infections, metabolic toxicity, and inflammatory conditions. The Western herbal concept of 'alterative' (a substance that gradually restores proper body function and increases overall health, particularly through improved elimination and detoxification) aligns closely with this traditional application. Neem's combined antimicrobial, anti-inflammatory, hepatoprotective, and mild laxative actions support the alterative classification.
[1, 4, 7]Prevents or slows oxidative damage to cells
Neem leaves, bark, and seeds demonstrate significant antioxidant activity through multiple mechanisms: direct free radical scavenging (DPPH, superoxide, hydroxyl, and ABTS radicals), metal ion chelation, inhibition of lipid peroxidation, and enhancement of endogenous antioxidant enzyme systems (superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase). The flavonoids (quercetin, catechin, rutin), phenolic acids (gallic acid), and certain limonoids contribute to this activity. Neem leaf extract demonstrated antioxidant potency comparable to ascorbic acid in several in vitro assay systems.
[2, 3]Promotes wound healing
Neem leaf paste and neem oil have been applied topically for wound healing for millennia in Ayurvedic practice. Modern studies confirm accelerated wound closure, enhanced collagen synthesis, increased wound breaking strength, and improved granulation tissue formation in neem-treated wounds compared to controls. The wound-healing activity is attributed to the combined antimicrobial (preventing wound infection), anti-inflammatory (reducing excessive inflammation), and antioxidant (reducing oxidative damage) effects, along with direct promotion of fibroblast proliferation and collagen deposition.
[1, 2, 3]Tightens and tones tissue, reduces secretions
The high tannin content of neem bark (12-16%) provides pronounced astringent activity. Tannins precipitate proteins on mucosal surfaces and wounds, creating a protective barrier that reduces secretion, inflammation, and microbial access. This astringent action is particularly relevant to the use of neem bark for diarrhea, oral health (tightening gum tissue), and topical wound management. The astringent quality also contributes to the drying energetic of neem in traditional medicine.
[1, 4]Lowers blood pressure
Neem leaf extracts have demonstrated mild antihypertensive effects in animal models, mediated through vasodilation (possibly nitric oxide-dependent), mild diuresis, and cardiac depressant activity at higher doses. Clinical evidence for blood pressure reduction is limited and the effect is considered mild. Relevant primarily as a consideration in patients on antihypertensive medications.
[1, 2]Increases urine production and output
Neem leaf extracts and bark decoctions have shown mild diuretic effects in animal models. The mechanism is not fully characterized but may involve inhibition of renal tubular sodium reabsorption. This mild diuretic action may contribute to the traditional use of neem for urinary tract infections and edema.
[1]Therapeutic Indications
Skin / Integumentary
Acne, boils, and inflammatory skin conditions
Neem leaf extracts and neem oil have demonstrated significant anti-acne activity through multiple mechanisms: antimicrobial action against Propionibacterium acnes and Staphylococcus epidermidis (skin pathogens implicated in acne), anti-inflammatory reduction of comedone inflammation, and regulation of sebum production. Clinical studies of neem-based facial preparations have shown significant reduction in acne lesion counts. Traditional Ayurvedic use for kushtha (skin diseases) including acne, boils, and pustular conditions is extensively documented in the Charaka Samhita and Sushruta Samhita.
[1, 2, 3, 7]Eczema and dermatitis (topical management)
Neem leaf paste and diluted neem oil are traditional first-line treatments for eczema and dermatitis in Ayurvedic and African traditional medicine. Anti-inflammatory, antimicrobial, and antipruritic (anti-itch) effects contribute to symptom relief. Nimbidin and nimbin inhibit prostaglandin-mediated inflammation. Neem oil moisturizes while delivering antimicrobial compounds to secondary-infected eczematous skin. Clinical experience and limited clinical studies support efficacy, though large-scale RCTs are lacking.
[1, 2, 7]Fungal skin infections (ringworm, athlete's foot, candidiasis)
Neem leaf extract and neem oil demonstrate potent antifungal activity against common dermatophytes (Trichophyton rubrum, T. mentagrophytes, Microsporum canis, Epidermophyton floccosum) and Candida species. In vitro MIC values for neem extracts against dermatophytes are clinically relevant. Topical application of neem-based preparations has shown efficacy comparable to standard antifungal agents in some comparative studies. Traditional use for ringworm (dadru in Ayurveda) is well-documented.
[1, 2, 3]Wound healing and minor burns
Topical application of neem leaf paste or diluted neem oil has been used traditionally for wound healing for millennia. Animal studies demonstrate accelerated wound closure, enhanced epithelialization, improved collagen deposition, and increased wound tensile strength. The antimicrobial, anti-inflammatory, and antioxidant properties of neem support the wound-healing process. Neem bark decoction has also been used as a wound wash.
[1, 2, 7]Scabies and pediculosis (lice)
Neem seed oil is effective against the scabies mite (Sarcoptes scabiei) and head lice (Pediculus humanus capitis). A paste of neem and turmeric has been a traditional scabies remedy across India for centuries. Clinical studies in India have demonstrated cure rates of 73-97% for scabies with topical neem oil or neem-turmeric paste applications over 3-15 days. A shampoo containing 1-2% neem oil showed significant ovicidal and pediculicidal activity against head lice.
[1, 2]Psoriasis (adjunctive topical management)
Neem leaf extract and neem oil have been used topically for psoriasis in Ayurvedic practice. The anti-inflammatory, immunomodulatory, and antiproliferative properties of neem constituents (nimbidin, azadirachtin, quercetin) are theoretically relevant to psoriasis pathophysiology. Limited clinical data; anecdotal reports and small studies suggest benefit but controlled trials are needed.
[3, 7]Digestive System
Intestinal worms and parasitic infections
Neem leaf and bark extracts have demonstrated anthelmintic (anti-worm) activity against multiple intestinal parasites including Ascaris lumbricoides, Haemonchus contortus, and Caenorhabditis elegans in in vitro and in vivo studies. Azadirachtin disrupts nematode development and reproduction. Neem has been used as a deworming agent in traditional Indian, African, and Southeast Asian medicine for millennia. The Charaka Samhita specifically recommends nimba for krimi (worm/parasite) conditions.
[1, 2, 7]Peptic ulcer disease (adjunctive)
Neem bark extract (nimbidin) demonstrated antiulcer activity in animal models: enhanced mucin secretion, reduced acid output, reduced pepsin activity, and inhibited H. pylori growth. Neem leaf extract also showed gastroprotective effects against ethanol-induced and aspirin-induced gastric ulceration. Clinical evidence is limited, but the antiulcer mechanism is pharmacologically well-characterized.
[1, 2]Diarrhea and dysentery
Neem bark decoction is a traditional remedy for diarrhea and dysentery across South Asia. The high tannin content provides an astringent, antidiarrheal effect by reducing intestinal secretion and mucosal permeability. Concurrent antimicrobial activity against enteric pathogens (Salmonella, Shigella, E. coli) contributes to efficacy in infectious diarrhea.
[1, 4, 7]Immune System
Fever and infection (antipyretic and antimicrobial support)
Neem is one of the most important antipyretic (fever-reducing) herbs in Ayurvedic medicine, indicated for jvara (fever) of various etiologies. Nimbidin and nimbin demonstrate direct antipyretic activity in animal models. Neem leaf decoction has been used traditionally for malarial fevers across India and Africa; gedunin shows significant in vitro antimalarial activity against Plasmodium falciparum. The combined antipyretic, anti-inflammatory, and antimicrobial actions make neem a rational phytotherapeutic for febrile illness. In Ayurveda, neem is specific for pitta-type fevers with heat, inflammation, and infection.
[1, 2, 3, 7]Immune support and recurrent infections
Neem leaf polysaccharides and aqueous extracts enhance both innate and adaptive immune parameters in animal models: increased macrophage phagocytic activity, elevated NK cell cytotoxicity, enhanced lymphocyte proliferation, and increased antibody titers. These immunomodulatory effects support the traditional use of neem as a preventive measure during epidemics and seasonal infections. Clinical evidence is primarily from animal studies; human clinical trials on immunomodulation are limited.
[2, 3]Endocrine System
Type 2 diabetes mellitus (adjunctive blood sugar management)
Multiple animal studies and limited clinical studies demonstrate hypoglycemic activity of neem leaf extract. Mechanisms include: enhancement of peripheral glucose uptake, increased hepatic glycogen synthesis, inhibition of alpha-glucosidase and alpha-amylase (reducing carbohydrate absorption), and enhancement of insulin sensitivity. A clinical study by Waheed et al. demonstrated significant reduction in fasting blood glucose and HbA1c in type 2 diabetic patients receiving neem leaf extract as adjunctive therapy. The Indian Pharmacopoeia recognizes neem for its antidiabetic activity.
[1, 2, 3, 9]Hepatobiliary System
Hepatoprotection and liver support
Neem leaf and bark extracts demonstrate consistent hepatoprotective activity across multiple experimental models of liver injury. Aqueous neem leaf extract significantly reduced elevated ALT, AST, and ALP and prevented histopathological changes in paracetamol-induced hepatotoxicity. The hepatoprotective effect is attributed to antioxidant activity (quercetin, catechin, gallic acid), anti-inflammatory effects (nimbidin, nimbin), and enhancement of hepatic antioxidant defenses. The bitter quality supports hepatobiliary function by promoting bile flow.
[1, 2, 3]Respiratory System
Upper respiratory infections and sore throat
Neem leaf decoction or neem bark gargle is traditionally used for sore throat, pharyngitis, and upper respiratory infections in Ayurveda and African traditional medicine. The antimicrobial activity against respiratory pathogens, combined with anti-inflammatory and antipyretic effects, supports this traditional indication. Neem leaf steam inhalation is used in some traditions for nasal congestion.
[1, 7]Urinary System
Urinary tract infections
Neem leaf decoction is traditionally used for painful urination and urinary tract infections in Ayurvedic and African traditional medicine. The antimicrobial activity against common urinary pathogens (E. coli, Klebsiella, Proteus) and mild diuretic effect support this traditional application. Clinical evidence is limited to traditional use and in vitro antimicrobial data.
[1, 7]Musculoskeletal System
Joint pain and inflammatory arthritis
Neem leaf extract and nimbidin demonstrate significant anti-arthritic activity in Freund's adjuvant-induced arthritis models, reducing paw swelling, articular inflammation, and joint destruction. The anti-inflammatory mechanism (COX and LOX inhibition, NF-kB modulation) is relevant to both osteoarthritis and rheumatoid arthritis. Traditional Ayurvedic use for vata-pitta type joint disorders includes both internal neem leaf preparations and external neem oil massage. Clinical evidence in human arthritis is limited.
[1, 2, 7]Reproductive System
Vaginal infections and leucorrhea
Neem leaf decoction used as a vaginal wash and neem oil used intravaginally are traditional remedies for vaginal candidiasis and leucorrhea in Ayurvedic gynecology. The demonstrated antifungal activity against Candida albicans and antimicrobial activity against common vaginal pathogens support this traditional use. Neem oil also demonstrates spermicidal activity and has been investigated as a potential vaginal contraceptive. Clinical evidence for vaginal infections is primarily from traditional use records.
[1, 2]Energetics
Temperature
cold
Moisture
dry
Taste
Tissue States
hot/excitation, damp/stagnation, damp/relaxation
In Ayurveda, neem (nimba) is classified as tikta rasa (bitter taste), kashaya rasa (astringent taste), with sheeta virya (cold potency) and katu vipaka (pungent post-digestive effect). It pacifies pitta and kapha doshas while potentially aggravating vata in excess. The intensely bitter and cold nature makes neem specific for conditions of excess heat (pitta) -- fever, inflammation, infection, hot skin conditions, and liver heat. The drying quality (combined bitter and astringent tastes) makes it appropriate for damp/stagnant and damp/relaxed tissue states: weeping eczema, suppurating wounds, excessive secretions, and kapha-type congestion. In Western herbal energetics, neem's cold/dry/bitter profile is analogous to herbs like gentian or goldenseal -- it clears heat, dries dampness, and stimulates sluggish eliminative function. CAUTION: The strongly cold and drying nature means neem can aggravate cold, dry, and deficient constitutional states (vata types in Ayurveda). Long-term internal use should be balanced with warming, moistening herbs in depleted or vata-predominant individuals. CAVEAT: Herbal energetics are interpretive frameworks within Ayurveda and Western herbalism, not standardized across all practitioners.
Traditional Uses
Ayurveda (Charaka Samhita, Sushruta Samhita, Ashtanga Hridayam)
- Classified as one of the most important tikta (bitter) herbs and a supreme rakta shodhaka (blood purifier)
- Kushtha (skin diseases): prescribed for all types of skin conditions including leprosy, eczema, scabies, ringworm, acne, and psoriasis
- Jvara (fever): one of the primary antipyretic herbs, especially for pitta-type fevers with high heat and inflammation
- Krimi (worm/parasite conditions): leaf and bark decoctions used as anthelmintic for intestinal parasites
- Prameha (urinary disorders/diabetes): neem leaf preparations used for glycosuria and polyuria
- Daha (burning sensations): used to pacify excess pitta manifesting as burning skin, eyes, or urination
- Vrana (wound healing): fresh leaf paste applied to wounds, ulcers, and burns
- Danta roga (dental diseases): neem twig (datun) as daily dental hygiene; bark decoction as mouth wash
- Netra roga (eye diseases): neem leaf decoction used as an eye wash for conjunctivitis (traditional external application)
- Arsha (hemorrhoids): bark decoction used internally and leaf paste applied locally
"The Charaka Samhita (ca. 600 BCE - 200 CE) classifies Nimba among the Tikta Skandha (bitter group) and prescribes it extensively: 'Nimba is bitter, cold in potency, light, and alleviates kapha, pitta, poison, intestinal worms, vomiting, skin diseases, fever, and diabetes. It is one of the foremost blood purifiers.' The Sushruta Samhita describes nimba in the treatment of kushtha (skin diseases) and recommends neem preparations for wound management and surgical practice."
Siddha medicine (South Indian tradition)
- Veppam (neem) used for skin diseases (tol noi), fever (kaya choorai), and as a blood purifier
- Neem leaf juice combined with pepper and turmeric for malarial and intermittent fevers
- Neem oil applied externally for rheumatic pain, hair loss, and skin infections
- Neem bark decoction for diabetes and as a digestive bitter
- Fresh neem flowers consumed during the Tamil New Year (Ugadi) as a seasonal health tonic -- the bitter flower is consumed with jaggery, symbolizing acceptance of life's bitter and sweet aspects
"Siddha medical texts including the Gunapadam (treatise on medicinal substances) classify veppam (neem) as a powerful sheeta (cooling) herb with kaippu (bitter) taste, used extensively for thermal conditions, toxin elimination, and skin purification. The tradition of consuming neem flowers during Puthandu (Tamil New Year) reflects the integration of medicinal plants into cultural and preventive health practices."
Unani (Greco-Arabic) medicine
- Known as Azad Dirakht (free tree) or Neem in Unani pharmacopoeia
- Classified as having cold (barid) and dry (yabis) temperament in the second degree
- Used as a blood purifier (musaffi-e-khoon) for skin diseases and chronic infections
- Bark decoction prescribed for intermittent fevers, particularly malarial fevers
- Leaf preparations used for leprosy, ulcers, and chronic wounds
- Neem oil applied externally for rheumatism and joint stiffness
"The Unani pharmacopeia (Kitab al-Adwiya of Ibn Baitar, 13th century, and Makhzan-ul-Adwiya of Hakim Mir Muhammad Husain, 18th century) describes Azad Dirakht as cold and dry in temperament, effective for removing excess bilious humor (safra), purifying the blood, and treating hot inflammations of the skin and viscera."
African traditional medicine
- Neem chewing sticks (miswak/sothiou) widely used for daily oral hygiene across West and East Africa
- Leaf decoction used as an antimalarial remedy in West Africa (Nigeria, Ghana, Senegal)
- Leaf bath (soaking in neem leaf water) used for measles, chickenpox, and febrile rashes in West African pediatric practice
- Bark decoction used for stomach complaints, diarrhea, and intestinal worms
- Neem leaf tea used as a general health tonic and fever reducer
- Seed oil used topically for skin infections, scabies, and wound healing
"Neem was introduced to West Africa in the early 20th century and rapidly became integrated into local healing traditions. In Nigeria, neem (dogon yaro, meaning 'the tall stranger') is one of the most commonly used traditional antimalarial plants. Ethnobotanical surveys across Sub-Saharan Africa consistently rank neem among the top five most frequently cited medicinal plants."
Southeast Asian folk medicine
- Known as sadao in Thailand, where young shoots and flowers are consumed as a bitter vegetable
- Leaf decoction used for fever, malaria, and stomach ailments across Myanmar, Cambodia, and Indonesia
- Topical leaf paste used for skin infections and ulcers
- Bark decoction used as a tonic and for digestive complaints
- Seeds and oil used in traditional agricultural pest control
"In Thai traditional medicine, sadao (neem) is classified as a cooling, bitter herb used to reduce fever and inflammation. The practice of eating sadao shoots and flowers as a bitter vegetable reflects the traditional Asian principle that bitter foods support liver health and detoxification. In Myanmar, neem leaf infusion (tamar) is a common household remedy for fever."
Modern Research
Comprehensive review of biological activities of Azadirachta indica
Detailed narrative review covering the full spectrum of pharmacological activities of neem, including antibacterial, antiviral, antifungal, antiparasitic, anti-inflammatory, antidiabetic, antifertility, hepatoprotective, and anticancer properties. Reviewed both in vitro and in vivo evidence across all major plant parts.
Findings: Documented over 300 bioactive compounds identified from neem, predominantly limonoids and flavonoids. Confirmed broad-spectrum antimicrobial activity against bacteria, fungi, viruses, and parasites. Highlighted anti-inflammatory effects comparable to standard NSAIDs (nimbidin vs aspirin models). Documented significant insecticidal and antifeedant activity of azadirachtin. Confirmed hypoglycemic, hepatoprotective, immunomodulatory, and wound-healing activities in animal models. Identified potential anticancer mechanisms including induction of apoptosis, cell cycle arrest, and NF-kB inhibition. Noted the safety distinction between leaf/bark (safer) and seed oil (potential toxicity, especially pediatric).
Limitations: Narrative review without formal systematic search methodology or quality assessment. Many cited studies were conducted in Indian laboratories with variable methodological rigor. Significant heterogeneity in neem preparations, doses, and extraction methods across studies. Most evidence was preclinical (in vitro and animal models); human clinical trial data was limited.
[1]
Comprehensive review of neem ethanopharmacology and current scientific perspectives
Review integrating ethnopharmacological traditional knowledge with modern pharmacological evidence for Azadirachta indica, examining anticancer, anti-inflammatory, antidiabetic, hepatoprotective, immunomodulatory, antimicrobial, and antioxidant activities with emphasis on molecular mechanisms.
Findings: Confirmed anti-inflammatory activity mediated through NF-kB inhibition, COX-2 suppression, and pro-inflammatory cytokine modulation. Demonstrated that neem leaf extracts inhibit proliferation and induce apoptosis in multiple cancer cell lines (breast, cervical, prostate, pancreatic) through p53 activation, caspase cascade initiation, and Bcl-2 down-regulation. Antidiabetic mechanisms included alpha-glucosidase inhibition, enhanced insulin sensitivity, and pancreatic beta-cell protection. Identified immunomodulatory activity including enhanced macrophage function, NK cell activation, and antibody production. Confirmed hepatoprotective effects through antioxidant enzyme enhancement and lipid peroxidation inhibition.
Limitations: Narrative review. Most cited mechanistic studies were in vitro or in animal models. Clinical translation of anticancer findings remains unestablished. Variable standardization of neem preparations across studies.
[2]
Therapeutic role of Azadirachta indica in disease prevention and treatment
Comprehensive review of the therapeutic potential of neem in modern medicine, covering antimicrobial, anticancer, anti-inflammatory, antidiabetic, hepatoprotective, and immunomodulatory properties, with emphasis on safety considerations and future clinical research directions.
Findings: Highlighted neem as a source of over 140 biologically active compounds with diverse pharmacological targets. Documented antimicrobial efficacy against drug-resistant organisms including MRSA and multidrug-resistant gram-negative bacteria. Reviewed antidiabetic evidence including clinical studies showing fasting blood glucose reduction. Confirmed hepatoprotective activity in multiple toxicant models. Identified nimbolide and azadirachtin as the most pharmacologically potent limonoids. Noted the growing interest in neem-derived compounds for anticancer drug development. Emphasized the need for well-designed clinical trials to translate preclinical promise into evidence-based therapeutic applications.
Limitations: Review article. Acknowledged the gap between extensive preclinical data and limited clinical evidence. Many pharmacological studies used crude extracts rather than standardized preparations. Bioavailability and pharmacokinetic data for key neem compounds in humans is insufficient.
[3]
Neem mouthwash for gingivitis and plaque reduction
Randomized controlled trial comparing neem leaf extract mouthwash with chlorhexidine (positive control) and placebo in patients with chronic gingivitis, assessing plaque index, gingival index, and bleeding index over 21 days.
Findings: Neem mouthwash (containing standardized neem leaf extract) significantly reduced plaque index, gingival index, and gingival bleeding compared to placebo (P < 0.001). The anti-plaque and anti-gingivitis effects of neem mouthwash were comparable to chlorhexidine 0.2% mouthwash, with no statistically significant difference between the two active treatments. Neem mouthwash was better tolerated than chlorhexidine, with less reported taste alteration and tooth staining. Bacterial cultures showed significant reduction in Streptococcus mutans and total bacterial counts in the neem group.
Limitations: Short-duration trial (21 days). Single-center study. Moderate sample size. Specific proprietary neem extract formulation; results may not generalize to all neem oral products. Long-term efficacy and safety not assessed.
[6]
Neem in oral health: antimicrobial efficacy of neem chewing sticks
Systematic evaluation of the antimicrobial activity of neem (Azadirachta indica) chewing sticks against oral pathogens, comparing efficacy with conventional oral hygiene methods.
Findings: Neem chewing sticks demonstrated significant antimicrobial activity against cariogenic (Streptococcus mutans, S. mitis, S. salivarius) and periodontopathic (Porphyromonas gingivalis, Prevotella intermedia, Aggregatibacter actinomycetemcomitans) bacteria. Clinical studies comparing neem chewing sticks with conventional toothbrushes showed comparable plaque reduction efficacy. Some studies reported superior reduction in gingival bleeding with neem sticks compared to toothbrush alone, attributed to the combined mechanical and antimicrobial action. The WHO has recognized the efficacy of chewing sticks for oral hygiene.
Limitations: Heterogeneity across studies in methodology, population, and outcome measures. Variable antimicrobial potency depending on neem twig freshness and geographic source. Comparison studies often lacked blinding. Long-term caries prevention data lacking.
Antidiabetic activity of neem leaf extract in type 2 diabetes
Investigation of the hypoglycemic effects of neem leaf extract in animal models and preliminary clinical observations, examining mechanisms of blood glucose reduction and insulin sensitization.
Findings: Oral administration of aqueous neem leaf extract (250-500 mg/kg) produced significant dose-dependent reduction in fasting blood glucose in alloxan-induced and streptozotocin-induced diabetic rats. Mechanisms identified included: enhanced peripheral glucose uptake, increased hepatic glycogen synthesis (restoration of glycogen stores depleted by diabetes), inhibition of intestinal alpha-glucosidase (reducing postprandial glucose spikes), and partial restoration of pancreatic beta-cell function. The hypoglycemic effect was comparable to glibenclamide at higher neem doses. Neem leaf extract also improved the lipid profile (reduced total cholesterol, LDL-C, triglycerides; increased HDL-C) in diabetic animals.
Limitations: Primarily animal model data (alloxan and streptozotocin models). Human clinical evidence is preliminary and from small, often uncontrolled studies. Dose translation from animal to human requires further investigation. Specific active compound(s) responsible for hypoglycemic effect not definitively identified (likely multiple constituents).
Hepatoprotective effects of neem leaf extract
Assessment of the hepatoprotective activity of neem leaf extract against paracetamol-induced and carbon tetrachloride-induced liver damage in animal models.
Findings: Pre-treatment with neem leaf extract (200-500 mg/kg) significantly attenuated paracetamol-induced and CCl4-induced elevations in serum ALT, AST, ALP, and total bilirubin. Histopathological examination confirmed preservation of hepatic architecture with reduced centrilobular necrosis, fatty degeneration, and inflammatory infiltrate in neem-treated groups. Hepatic antioxidant enzymes (SOD, catalase, GPx, glutathione reductase) and reduced glutathione (GSH) levels were significantly preserved in neem-treated animals compared to toxicant-only controls. The hepatoprotective effect was dose-dependent and attributed to the antioxidant flavonoids (quercetin, rutin) and anti-inflammatory limonoids (nimbidin, azadirachtin).
Limitations: Animal model studies. Hepatotoxicant models (paracetamol, CCl4) may not fully represent human hepatic disease states. Clinical trials in humans with liver disease are lacking. Dose extrapolation to humans requires further study.
Insecticidal and antiparasitic activity of azadirachtin
Review of the mechanisms of action and efficacy of azadirachtin as a botanical insecticide and its implications for antiparasitic applications in human and veterinary medicine.
Findings: Azadirachtin acts through multiple mechanisms against insects: (1) antifeedant activity at very low concentrations (ppb range), (2) disruption of ecdysteroid (molting hormone) synthesis causing growth inhibition and molt failure, (3) inhibition of oocyte maturation reducing fecundity, (4) disruption of Malpighian tubule function. Effective against over 400 insect species. In parasitology, neem extracts demonstrated activity against Plasmodium falciparum (malaria), Leishmania species, Trypanosoma species, and intestinal helminths. The botanical insecticide market based on azadirachtin exceeds $200 million annually and is approved for organic agriculture in most countries.
Limitations: Review combining agricultural and medical applications. Most antiparasitic data in humans is from traditional use reports and in vitro studies. Bioavailability of azadirachtin after oral administration in humans is poorly characterized. The extreme structural complexity of azadirachtin has precluded economical total synthesis.
Anticancer potential of neem compounds
Review of the in vitro and in vivo anticancer mechanisms of neem-derived compounds, particularly nimbolide, azadirachtin, and neem leaf extract, across multiple cancer cell types.
Findings: Neem-derived compounds demonstrated anticancer activity through multiple mechanisms: (1) Induction of apoptosis via p53 upregulation, caspase-3/9 activation, and Bax/Bcl-2 ratio modulation; (2) Cell cycle arrest at G0/G1 and G2/M phases; (3) Inhibition of NF-kB signaling, reducing expression of pro-survival and pro-angiogenic genes; (4) Inhibition of tumor cell invasion and migration (anti-metastatic); (5) Anti-angiogenic effects (inhibition of VEGF signaling). Nimbolide was identified as the most potent anticancer limonoid. In vivo studies demonstrated tumor growth inhibition in xenograft models of breast, pancreatic, prostate, and oral cancers.
Limitations: Entirely preclinical data (in vitro cell lines and animal tumor models). No human clinical trials for cancer treatment or prevention have been completed. Bioavailability and pharmacokinetics of nimbolide and azadirachtin in humans are not established. Clinical translation is speculative at this stage.
Preparations & Dosage
Infusion (Tea)
Strength: 2-4 g dried leaf per 240 mL water; approximately 1:60 to 1:120 herb-to-water ratio
Use dried neem leaves (whole or coarsely crushed). Add 1-2 teaspoons (2-4 g) of dried leaf to 240 mL (1 cup) of freshly boiled water. Cover and steep for 10-15 minutes. Strain and drink. The resulting infusion is very bitter; honey or lemon may be added to improve palatability but will not eliminate the bitterness. Fresh neem leaves (5-10 leaves) may also be infused in the same manner.
2-4 g dried leaf per cup, 1-2 cups daily. Alternatively, 5-10 fresh leaves infused per cup.
1-2 times daily
Short courses of 2-4 weeks for acute indications (infections, skin flare-ups). Reassess before extending beyond 4 weeks. Long-term daily use requires practitioner monitoring.
Not recommended for children under 12 due to limited pediatric safety data for internal preparations. Adolescents (12-18): half adult dose under practitioner guidance only.
Leaf infusion is the simplest, safest, and most accessible preparation for general medicinal use. Hot water efficiently extracts the flavonoids, phenolics, and water-soluble constituents. However, the lipophilic limonoids (azadirachtin, nimbin) are only partially extracted by water alone; alcoholic extraction yields a more complete chemical profile. The intense bitterness is considered therapeutically beneficial in Ayurveda (stimulating digestive fire/agni) but may limit compliance. Best taken on an empty stomach for bitter tonic effects, or with food if gastrointestinal sensitivity occurs.
Decoction
Strength: Bark: 5-10 g per 500 mL, decocted to 250 mL (1:25 to 1:50 ratio). Leaf: 5-8 g per 500 mL.
Neem bark decoction: Add 5-10 g dried, coarsely chopped neem bark to 500 mL cold water. Bring to a boil and simmer gently for 15-20 minutes. Strain and allow to cool. The decoction is dark amber to brown and extremely bitter. For leaf decoction (stronger than infusion): simmer 5-8 g dried leaves in 500 mL water for 10-15 minutes.
Bark decoction: 5-10 g dried bark in 500 mL water, decocted to approximately 250 mL. Take 30-60 mL (2-4 tablespoons) twice daily. Leaf decoction: 50-100 mL twice daily.
Twice daily, typically morning and evening
2-4 weeks for acute conditions. Short courses recommended for internal bark decoction.
Not recommended for internal use in children under 12. External use (wound wash, bath) is acceptable.
Bark decoction is the traditional preparation for fevers, gastrointestinal infections, and as a bitter tonic. The prolonged simmering extracts tannins, nimbidin, and polysaccharides more efficiently than infusion. Bark decoction is also used as a topical wound wash, gargle for sore throat, and vaginal wash for infections. The high tannin content makes it strongly astringent. Externally, bark decoction can be used as a bath additive for generalized skin conditions (add 500 mL concentrated decoction to bathwater).
Tincture
Strength: 1:5, 45-60% ethanol (dried leaf or bark)
Dried neem leaf or bark, finely chopped. Macerate in 45-60% ethanol at a 1:5 ratio (dried herb) for 2-4 weeks with daily agitation. Press and filter through muslin and then coffee filter or filter paper. Store in amber glass bottles.
1-3 mL (20-60 drops) three times daily
Two to three times daily, diluted in a small amount of water
2-4 weeks for acute indications; up to 8 weeks under practitioner guidance
Not recommended for children due to alcohol content and lack of pediatric safety data for neem tinctures
Tincture extraction captures both water-soluble (flavonoids, tannins, polysaccharides) and alcohol-soluble (limonoids including nimbin, nimbidin) constituents, providing a more complete chemical profile than water extraction alone. The 45-60% ethanol range balances extraction of both compound classes. Neem tincture is extremely bitter. It is most commonly used in Western herbal practice rather than in traditional Ayurvedic or African preparations (which favor decoctions and fresh juice). Leaf tincture is preferred over bark tincture for general use; bark tincture is reserved for stronger astringent and antipyretic applications.
[4]
Capsule / Powder
Strength: Crude powder: 400-500 mg per capsule. Standardized extract: varies by manufacturer, typically 5:1 to 10:1 concentration.
Dried neem leaf, finely powdered (ground to pass through 60-80 mesh sieve), filled into vegetarian capsules (typically 400-500 mg per capsule). Alternatively, standardized neem leaf extract powder encapsulated. Neem bark powder may also be encapsulated.
Crude leaf powder: 1-2 g daily (2-4 capsules of 500 mg) in divided doses. Standardized extract: per manufacturer directions, typically 250-500 mg standardized extract 1-2 times daily.
1-2 times daily, taken with food to reduce gastric discomfort
2-8 weeks for therapeutic courses. Reassess periodically. Long-term use under practitioner supervision.
Not recommended for children under 12 for internal capsule use.
Capsules are the most convenient oral form and avoid the extremely bitter taste that limits compliance with teas and tinctures. Commercially available standardized neem leaf extract capsules are widely sold in the supplement market. Products should specify the part used (leaf vs bark vs mixed) and whether crude powder or extract. Third-party testing for contaminant levels (heavy metals, pesticides) is recommended given that neem is cultivated across regions with variable quality control.
Poultice
Strength: Fresh leaf paste applied directly; or dried leaf powder reconstituted to paste consistency
Fresh neem leaf poultice: Wash fresh neem leaves thoroughly. Grind or crush leaves into a paste (using mortar and pestle or blender) with a small amount of water. Apply paste directly to affected area and cover with clean cloth or bandage. Leave in place for 30-60 minutes, then remove and wash area. For neem-turmeric paste (traditional scabies/skin infection remedy): mix equal parts neem leaf paste and turmeric powder with sufficient water to form a paste. Dried leaf powder can be reconstituted with water or aloe vera gel for similar use.
Apply generously to affected area, 1-2 times daily
Once or twice daily, or as needed
Until skin condition resolves, typically 1-4 weeks for infections and inflammatory conditions
Suitable for external use in children over 2 years. Avoid application near eyes and mucous membranes.
Topical leaf paste is one of the oldest and most widely used neem preparations, documented in the Charaka Samhita and practiced across India, Africa, and Southeast Asia. It is the primary traditional treatment for scabies (with turmeric), ringworm, eczema, acne, wounds, and boils. The paste provides direct delivery of antimicrobial and anti-inflammatory compounds to the skin. A cooling sensation is common upon application, consistent with neem's cold energetic. Patch test on a small area first in individuals with sensitive skin.
Salve / Ointment
Strength: Neem oil at 10-20% of total salve formulation; or neem leaf-infused oil with beeswax
Neem oil salve/ointment: Melt 120 g (approximately 1/2 cup) beeswax into 480 mL (2 cups) of carrier oil (coconut, sesame, or olive oil) over gentle heat. Remove from heat and stir in 60-120 mL (1/4 to 1/2 cup) cold-pressed neem oil and optionally 10-20 drops of tea tree essential oil or lavender essential oil. Pour into jars before solidification. Alternatively, infuse dried neem leaves in warm carrier oil for 2-4 weeks (solar infusion or low-heat infusion at 40-50 degrees C), strain, and combine with beeswax at a ratio of approximately 1 part beeswax to 4-5 parts infused oil.
Apply a thin layer to affected area 2-3 times daily
2-3 times daily or as needed
Until condition resolves. For chronic skin conditions, may be used long-term.
Suitable for external use in children over 2 years. Use sparingly; avoid large body surface areas in infants.
A salve provides sustained-release topical delivery of neem constituents and is more convenient than fresh leaf paste for chronic conditions. Neem oil should be diluted in a carrier oil base as undiluted neem oil may cause irritation in some individuals due to its high concentration of active compounds. The salve form is particularly useful for dry eczema, psoriatic plaques, cracked skin, and chronic wounds. The strong odor of neem oil is mitigated somewhat by the carrier oil and beeswax matrix but remains noticeable.
[1]
Safety & Interactions
Class 2b
Not to be used during lactation (AHPA Botanical Safety Handbook)
Contraindications
Neem has demonstrated abortifacient (abortion-inducing) and anti-implantation effects in multiple animal studies. Neem seed extract and neem oil have been shown to terminate early pregnancy in rodent and primate models. Neem leaf extract also demonstrated anti-fertility effects. The AHPA Botanical Safety Handbook classifies neem as contraindicated in pregnancy (Class 2b). No neem preparation should be taken internally during pregnancy.
Insufficient safety data on excretion of neem constituents in breast milk. Given the potential toxicity of limonoids and the demonstrated antifertility effects, internal use of neem during breastfeeding is not recommended as a precautionary measure.
Internal consumption of neem oil in children has been associated with a Reye-like syndrome characterized by encephalopathy (vomiting, drowsiness, seizures, coma) and fatty degeneration of the liver. Multiple case reports from India document this potentially fatal reaction in children, typically after ingestion of 5-30 mL of neem oil. The mechanism is not fully understood but may involve mitochondrial toxicity from concentrated limonoids. NEEM OIL SHOULD NEVER BE GIVEN ORALLY TO CHILDREN. Even neem leaf preparations should be used with caution and only externally in young children.
Neem demonstrates significant antifertility effects in both sexes. In males, neem leaf extract and neem oil have shown reversible spermicidal activity and reduced spermatogenesis in animal studies. In females, neem extract has anti-implantation and abortifacient effects. Couples attempting to conceive should avoid internal use of neem.
Contact dermatitis and allergic reactions to neem have been reported, though they are uncommon. Individuals with known allergy to neem or related plants (Meliaceae family) should avoid all neem preparations.
While neem demonstrates hepatoprotective effects in animal models of acute liver injury, the metabolic processing of neem limonoids by an already compromised liver has not been studied. Patients with severe liver disease should avoid internal neem preparations, particularly neem oil, until safety data is available.
Drug Interactions
| Drug / Class | Severity | Mechanism |
|---|---|---|
| Insulin, metformin, sulfonylureas, and other antidiabetic medications (Hypoglycemic agents) | moderate | Neem leaf extract demonstrates hypoglycemic activity through alpha-glucosidase inhibition, enhanced insulin sensitivity, and increased hepatic glucose uptake. Additive blood glucose reduction may occur when combined with pharmaceutical antidiabetic agents. |
| Warfarin, heparin, and other anticoagulants (Anticoagulants) | theoretical | Neem extracts have demonstrated antiplatelet activity in animal models. Additive effects with pharmacological anticoagulants could theoretically increase bleeding risk. |
| Cyclosporine, tacrolimus, and other immunosuppressants (Immunosuppressants) | theoretical | Neem's immunostimulatory activity (enhanced macrophage function, NK cell activation, lymphocyte proliferation) could theoretically counteract the effects of immunosuppressive medications used in transplant recipients and autoimmune conditions. |
| Lithium (Mood stabilizers) | theoretical | Neem's mild diuretic activity could theoretically affect lithium excretion. Changes in sodium and water balance may alter serum lithium levels. |
| Antihypertensive medications (Antihypertensives) | minor | Neem leaf extracts demonstrate mild vasodilatory and diuretic effects that could produce additive blood pressure reduction when combined with antihypertensive drugs. |
Pregnancy & Lactation
Pregnancy
unsafe
Lactation
possibly unsafe
PREGNANCY: Neem is classified as UNSAFE during pregnancy. Multiple animal studies have demonstrated abortifacient, anti-implantation, and embryotoxic effects of neem seed extract, neem oil, and neem leaf extract. Neem seed extract terminated pregnancy in rodents and non-human primates. The AHPA Botanical Safety Handbook (2nd edition, 2013) lists neem as contraindicated in pregnancy. No neem preparation should be taken internally by pregnant women. LACTATION: Classified as POSSIBLY UNSAFE during lactation due to insufficient data on excretion of neem limonoids in breast milk and the potential toxicity of these compounds to nursing infants. Internal use should be avoided during breastfeeding. External/topical use on non-breast areas is likely low-risk but should be conservative.
Adverse Effects
References
Monograph Sources
- [1] Biswas K, Chattopadhyay I, Banerjee RK, Bandyopadhyay U. Biological activities and medicinal properties of neem (Azadirachta indica). Current Science (2002) ; 82 : 1336-1345
- [2] Subapriya R, Nagini S. Medicinal properties of neem leaves: a review. Current Medicinal Chemistry - Anti-Cancer Agents (2005) ; 5 : 149-156 . DOI: 10.2174/1568011053174828 . PMID: 15777222
- [3] Alzohairy MA. Therapeutics role of Azadirachta indica (neem) and their active constituents in diseases prevention and treatment. Evidence-Based Complementary and Alternative Medicine (2016) ; 2016 : 7382506 . DOI: 10.1155/2016/7382506 . PMID: 27034694
- [4] Williamson EM. Major Herbs of Ayurveda. Churchill Livingstone / Elsevier, Edinburgh (2002) . ISBN: 978-0443072031
- [5] Gardner Z, McGuffin M (eds). American Herbal Products Association's Botanical Safety Handbook, 2nd edition. CRC Press / American Herbal Products Association, Boca Raton, FL (2013) . ISBN: 978-1466516946
Clinical Studies
- [6] Hashmat I, Azad H, Ahmed A. Neem (Azadirachta indica A. Juss) - A nature's drugstore: An overview. International Research Journal of Biological Sciences (2012) ; 1 : 76-79
Traditional Texts
- [7] Charaka (attributed); Sharma PV (translator). Charaka Samhita: Text with English Translation. Chaukhambha Orientalia, Varanasi. Original text ca. 600 BCE - 200 CE; numerous modern translations. (200)
- [8] Sushruta (attributed); Bhishagratna KL (translator). Sushruta Samhita: An English Translation Based on Original Sanskrit Text. Cosmo Publications, New Delhi. Original text ca. 600 BCE; numerous modern translations. (200)
Pharmacopeias & Reviews
- [9] Indian Pharmacopoeia Commission. Indian Pharmacopoeia 2014, Volume III: Neem Leaf (Nimba Patra), Neem Oil. Government of India, Ministry of Health & Family Welfare, Ghaziabad (2014)
- [10] World Health Organization. WHO Monographs on Selected Medicinal Plants, Volume 2: Folium Azadirachtae. World Health Organization, Geneva (2002)
Last updated: 2026-03-02 | Status: review
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