Herbal Monograph
Oregon Grape
Mahonia aquifolium (Pursh) Nutt.
Berberidaceae
Premier Western alterative for chronic skin conditions, liver support, and antimicrobial synergy
Overview
Plant Description
Oregon Grape is an erect, evergreen shrub growing 1-2 meters (3-6 feet) tall, occasionally reaching 3 meters under favorable conditions. The leaves are pinnately compound with 5-9 (occasionally 11) holly-like leaflets, each 3-8 cm long, with spiny-toothed margins reminiscent of English Holly (Ilex aquifolium) -- hence the species epithet 'aquifolium' (needle-leaved). Leaflets are glossy dark green above with a leathery texture, turning reddish-purple to bronze in autumn and winter. The bark of young stems is yellowish-green; older bark becomes grey-brown externally but reveals a vivid bright yellow inner bark and wood when cut, due to the high berberine content. Flowers are borne in dense terminal racemes of 20-60 small, bright yellow flowers in early to mid-spring (March-May). Each flower has 6 sepals, 6 petals, and 6 stamens. The fruits are small, round berries approximately 8-10 mm in diameter, borne in grape-like clusters, ripening from green through red to dark blue-purple with a glaucous bloom by late summer. The berries are edible but very tart and acidic. The root system produces bright yellow roots and rhizomes that spread by underground runners, forming colonial thickets. The vivid yellow color of the inner bark, wood, and roots is the most reliable field identification feature and is directly attributable to berberine and related isoquinoline alkaloids.
Habitat
Native to the Pacific Northwest of North America. Oregon Grape grows in the understory of coniferous and mixed forests, particularly Douglas fir (Pseudotsuga menziesii), Western red cedar (Thuja plicata), and Ponderosa pine (Pinus ponderosa) forests. It thrives in well-drained, slightly acidic to neutral soils in partial to full shade, though it tolerates full sun with adequate moisture. Found from low elevations to approximately 2,100 meters (7,000 feet). Commonly found on rocky slopes, forest margins, and in open woodland clearings.
Distribution
Native range extends from southern British Columbia and Alberta through Washington, Oregon, Idaho, and Montana, south through northern California and into the northern Rocky Mountain states (Wyoming, Utah, Colorado, Nevada). Oregon Grape is the state flower of Oregon (designated 1899). The species has been widely introduced as an ornamental landscape plant throughout Europe, the eastern United States, and other temperate regions, where it has occasionally naturalized and become locally invasive (particularly in parts of the United Kingdom and continental Europe).
Parts Used
Root bark (cortex radicis)
Preferred: Dried root bark for tincture, decoction, or powdered extract; standardized extract for topical preparations
The primary medicinal part used in Western herbal practice. Root bark contains the highest concentration of isoquinoline alkaloids, particularly berberine, jatrorrhizine, and palmatine. The vivid yellow color indicates alkaloid richness. Listed in the United States Pharmacopeia (USP) as Berberis aquifolium (under the older nomenclature). This is the part used in most clinical research on Oregon Grape, including the psoriasis studies.
Stem bark
Preferred: Dried bark for tincture or decoction
Secondary medicinal part. Contains the same alkaloid profile as root bark but at somewhat lower concentrations. More accessible to harvest sustainably as it does not require digging roots. Used interchangeably with root bark by some practitioners, particularly in tincture and decoction preparations.
Berries (fructus)
Preferred: Fresh or dried berries for food preparations; occasionally tincture
Minor medicinal use. The tart, acidic berries contain vitamin C, anthocyanins, and small amounts of berberine. Traditionally used to make jams, jellies, and beverages by Pacific Northwest Indigenous peoples. Not the primary medicinal part and not the focus of clinical research. The berries are safe to eat in moderate quantities but very sour raw.
Key Constituents
Isoquinoline alkaloids (protoberberine and bisbenzylisoquinoline types)
The isoquinoline alkaloids collectively are responsible for the primary therapeutic actions of Oregon Grape: antimicrobial, anti-inflammatory, anti-proliferative (keratinocyte), choleretic, and bitter tonic effects. The total alkaloid profile -- rather than berberine alone -- determines the clinical activity of whole-plant preparations. Stermitz et al. (2000) demonstrated that the plant also contains the compound 5'-methoxyhydnocarpin (5'-MHC), a potent inhibitor of bacterial NorA multidrug resistance efflux pumps, which dramatically enhances berberine's antimicrobial potency in the intact plant extract compared to isolated berberine. This synergy between berberine and 5'-MHC is a landmark example of whole-plant synergy in herbal medicine.
Multidrug resistance pump inhibitors
The presence of 5'-MHC alongside berberine in Oregon Grape root represents one of the best-documented examples of synergy in herbal medicine. The plant effectively produces both an antimicrobial compound (berberine) and a resistance-blocker (5'-MHC) in the same tissue, making the whole extract substantially more effective as an antimicrobial than isolated berberine. This has important implications for the use of whole-plant preparations versus isolated berberine supplements.
Tannins and polyphenols
Tannins and flavonoids play a supporting role in the overall therapeutic profile, contributing astringent, anti-inflammatory, and antioxidant effects that complement the primary alkaloid-driven actions. The berry anthocyanins have independent antioxidant value.
Herbal Actions
Gradually restores proper body function and increases overall health
Oregon Grape is one of the most highly regarded alterative (blood-cleansing) herbs in Western herbalism. The alterative action reflects its ability to improve metabolic processes through enhanced hepatic and biliary function, improved waste elimination, and anti-inflammatory effects on the skin and mucous membranes. The Eclectic physicians (19th-century American medical herbalists) considered Oregon Grape root one of the foremost alteratives, particularly for chronic skin conditions associated with liver sluggishness. The combination of choleretic, antimicrobial, and anti-inflammatory actions underlies the alterative classification. This is the classical indication that drives its use in psoriasis, eczema, and chronic skin diseases.
[2, 5]Berberine and related protoberberine alkaloids stimulate bile secretion (choleresis) by the hepatocytes and promote bile flow through the biliary tract. This action improves fat digestion, supports hepatic detoxification pathways, and enhances elimination of metabolic waste products via the bile. The choleretic effect is a key mechanistic basis for the traditional alterative action: by improving hepatobiliary function, Oregon Grape supports the body's ability to process and eliminate endogenous and exogenous toxins, which is reflected clinically in improved skin conditions.
[1, 2]Kills or inhibits the growth of microorganisms
Berberine demonstrates broad-spectrum antimicrobial activity in vitro against gram-positive bacteria (Staphylococcus aureus, Streptococcus spp., including MRSA at higher concentrations), gram-negative bacteria (E. coli, Klebsiella, Salmonella), fungi (Candida albicans and other Candida species), and protozoa (Giardia lamblia, Entamoeba histolytica). Critically, the whole Oregon Grape extract is more potent than isolated berberine due to the synergistic action of 5'-methoxyhydnocarpin (5'-MHC), which inhibits bacterial efflux pumps that would otherwise reduce intracellular berberine concentrations (Stermitz et al. 2000). This efflux pump inhibition is clinically significant for skin infections and may explain why topical whole-extract preparations are effective.
[7, 8]Reduces inflammation
Berberine inhibits NF-kB signaling, reduces pro-inflammatory cytokine production (IL-1beta, IL-6, TNF-alpha), and inhibits cyclooxygenase-2 (COX-2) and lipoxygenase. Muller and Ziereis (1994) demonstrated that Mahonia aquifolium extract inhibited lipoxygenase and lipid peroxidation, mechanisms directly relevant to the inflammatory component of psoriasis. The anti-inflammatory action is considered secondary because it complements rather than defines the primary therapeutic identity of Oregon Grape (which centers on the alterative/choleretic/antimicrobial triad).
[5, 7]Oregon Grape root bark is intensely bitter due to its isoquinoline alkaloid content. The bitter taste stimulates the bitter taste receptors (T2Rs) on the tongue and throughout the gastrointestinal tract, triggering a reflex increase in gastric acid secretion, pancreatic enzyme output, and bile flow. This bitter tonic action improves appetite, digestion, and nutrient absorption. In Western herbal tradition, Oregon Grape is classified as a 'cooling bitter' -- stimulating digestive secretions without adding metabolic heat -- making it suitable for conditions with signs of hepatic congestion and sluggish digestion.
[1, 2]Protects the liver from damage
Berberine and palmatine have demonstrated hepatoprotective effects in animal models, including reduction of liver enzyme elevation (ALT, AST) following toxic insult, inhibition of hepatic lipid accumulation, and enhancement of antioxidant enzyme activity in liver tissue. The hepatoprotective action is interlinked with the choleretic effect: by promoting healthy bile flow and reducing hepatic congestion, Oregon Grape supports overall liver function. This action is particularly relevant in the context of chronic skin disease, where hepatic sluggishness is considered a contributing factor in traditional Western herbalism.
[1]Berberine has a mild laxative effect, primarily through stimulation of bile secretion (which has a natural laxative effect in the intestines) and direct stimulation of intestinal smooth muscle contraction. The laxative effect is gentle and not comparable to strong purgatives. Oregon Grape is not used primarily as a laxative but the mild bowel-stimulating action contributes to its overall eliminative and alterative profile.
[1]Therapeutic Indications
dermatological
Psoriasis
The best-studied clinical indication for Oregon Grape. Bernstein et al. (2006) conducted a double-blind, placebo-controlled trial of Mahonia aquifolium cream (Relieva) in patients with mild-to-moderate psoriasis, demonstrating statistically significant improvement in PASI (Psoriasis Area and Severity Index) scores versus vehicle control. Wiesenauer and Ludtke (1996) conducted a large multicenter observational study (n=443) with Mahonia aquifolium homeopathic preparation showing significant improvement in psoriasis severity. Muller and Ziereis (1994) elucidated the mechanism: inhibition of keratinocyte proliferation and lipoxygenase activity by Mahonia alkaloids. Berberine inhibits the excessive keratinocyte proliferation characteristic of psoriatic plaques at concentrations achievable topically. The anti-inflammatory (lipoxygenase/COX-2 inhibition) and antimicrobial actions provide additional benefit.
[5, 6, 7]Eczema (atopic dermatitis)
Traditional use as an alterative for chronic eczema, particularly when associated with signs of liver sluggishness (poor digestion, constipation, coated tongue). The anti-inflammatory, antimicrobial, and hepatobiliary-stimulating actions collectively address the multiple factors contributing to chronic eczema. Topical Mahonia preparations may reduce inflammation and secondary bacterial colonization (particularly S. aureus, which colonizes eczematous skin). Limited clinical trial data specific to eczema, though the anti-proliferative and anti-inflammatory mechanisms demonstrated in psoriasis studies are relevant.
[2, 5]Acne vulgaris
Traditional use for acne, particularly when presenting with pustular lesions and associated with sluggish digestion. The antimicrobial activity against Cutibacterium acnes (formerly Propionibacterium acnes), anti-inflammatory action, and alterative/hepatobiliary support provide a rational basis for this indication. Topical application of Mahonia extract addresses local inflammation and bacterial colonization, while internal use supports the eliminative functions traditionally considered relevant to acne. Limited specific clinical evidence.
[1, 2]Seborrheic dermatitis
Used traditionally for scaly, inflammatory skin conditions including seborrheic dermatitis. The combination of antifungal activity (against Malassezia spp., the yeasts implicated in seborrheic dermatitis), anti-inflammatory action, and anti-proliferative effects on keratinocytes provides a rational basis. Limited clinical data specific to this condition.
[1]Hepatobiliary System
Liver stagnation and bile insufficiency
A core traditional indication based on the choleretic and hepatoprotective actions of the protoberberine alkaloids. Oregon Grape root is used when there are signs of hepatobiliary sluggishness: poor fat digestion, nausea after fatty meals, constipation, coated tongue, and chronic skin conditions. The bitter taste and choleretic action stimulate bile production and flow, relieving congestion. Eclectic physicians considered Oregon Grape root a prime hepatic stimulant for torpid liver states.
[1, 2]Cholestasis (mild, functional)
Traditional use for promoting bile flow in cases of functional bile stasis. The choleretic action of berberine has been demonstrated pharmacologically. Contraindicated in obstructive biliary conditions (gallstones obstructing the bile duct), where stimulation of bile flow could worsen the obstruction.
[1]Digestive System
Dyspepsia (functional indigestion)
Oregon Grape root bark's bitter tonic action stimulates gastric acid secretion, pancreatic enzyme production, and bile flow, collectively improving digestive function. Indicated for sluggish digestion with symptoms of bloating, fullness, poor appetite, and nausea, particularly after fatty meals. The bitter taste should be experienced directly for maximum reflex stimulation of digestive secretions -- tincture taken in water before meals is the preferred delivery method for this indication.
[1, 2]Gastrointestinal infections (bacterial and protozoal)
Berberine has demonstrated in vitro and in vivo antimicrobial activity against common GI pathogens including E. coli, Salmonella, Vibrio cholerae, Giardia lamblia, and Entamoeba histolytica. Clinical trials of berberine (typically from Berberis or Coptis species) have shown efficacy in infectious diarrhea, particularly traveler's diarrhea and giardiasis. While these studies used isolated berberine rather than Oregon Grape specifically, the berberine content provides a pharmacological basis for this indication. The whole extract may be more effective than isolated berberine due to 5'-MHC efflux pump inhibition.
[8]genitourinary
Urinary tract infections (adjunctive)
Traditional use as an antimicrobial for urinary tract infections. Berberine is partially excreted in the urine, providing some direct antimicrobial activity in the urinary tract. Oregon Grape is typically used in combination with other urinary antimicrobials (uva ursi, buchu) and demulcents (marshmallow root, corn silk) rather than as a standalone UTI treatment.
[1]Immune System
Antimicrobial support (topical and systemic)
The broad-spectrum antimicrobial activity of berberine and the synergistic efflux pump inhibition by 5'-MHC provide a well-characterized antimicrobial action. Topical application is particularly well-supported for skin infections and colonization (S. aureus in eczema and psoriasis). The efflux pump inhibition mechanism (Stermitz et al. 2000) suggests that whole Oregon Grape extract may be effective where isolated berberine is not, particularly against multidrug-resistant organisms.
[7, 8]Energetics
Temperature
cool
Moisture
dry
Taste
Tissue States
damp/stagnation, hot/excitation, damp/relaxation
In Western herbal energetics, Oregon Grape is classified as cool and dry -- a cooling bitter that clears heat and resolves dampness. The pronounced bitter taste indicates its affinity for the liver and gallbladder, stimulating hepatobiliary function and clearing stagnation. The cooling quality makes it well-suited for conditions presenting with signs of heat: inflammation, redness, irritability, and toxic accumulation. Oregon Grape specifically addresses damp/stagnation tissue states (sluggish liver, congested bile, boggy tissues, chronic skin eruptions with weeping or pustulation) and hot/excitation states (inflamed skin, red eruptions, irritability). It may also address damp/relaxation states where tissues are atonic and boggy. Oregon Grape is NOT suited for cold, deficient, or depleted constitutions -- it is a stimulating alterative that requires adequate vitality to work with. Prolonged use in cold, depleted individuals may further deplete digestive fire. Best combined with warming herbs (ginger, cinnamon) in constitutionally cold individuals. CAVEAT: Herbal energetics are interpretive frameworks within Western herbalism, not standardized across all practitioners.
Traditional Uses
Pacific Northwest Indigenous peoples
- Root bark decoction as a bitter tonic for stomach complaints, loss of appetite, and debility
- Yellow root bark used as a dye for baskets, clothing, and decorative items
- Root preparations for kidney and bladder complaints
- Berries eaten fresh or dried as food, made into pemmican mixtures, or prepared as beverages
- Root bark poultice applied externally for wounds, skin infections, and inflammatory skin conditions
- General tonic and blood purifier for chronic illness
"Numerous Pacific Northwest tribes including the Kwakwaka'wakw (Kwakiutl), Nlaka'pamux (Thompson), Okanagan-Colville, Shuswap, Haida, Tlingit, and others used Mahonia aquifolium extensively. The root bark was the primary medicinal part, valued for its intense bitterness and yellow color. The dye use was equally important culturally -- the vivid yellow color from berberine-rich bark was one of the most important traditional dyes in the Pacific Northwest region."
[4]
Eclectic medicine (19th-century American medical herbalism)
- Berberis aquifolium as a primary alterative for chronic skin diseases (psoriasis, eczema, acne, syphilitic skin eruptions)
- Hepatic stimulant for torpid liver with associated constipation and skin manifestations
- Bitter tonic for dyspepsia and loss of appetite
- Treatment of scrofula (tuberculous lymphadenitis) and constitutional syphilis
- Blood purifier in chronic rheumatic complaints
- Antimicrobial for gastrointestinal and urinary infections
"Felter and Lloyd's King's American Dispensatory (1898) provided an extensive monograph on Berberis aquifolium, describing it as 'one of the most certain and reliable alteratives in the materia medica.' The Eclectics specifically valued it for chronic skin disease with hepatic torpor, stating: 'It is a remedy for the scaly, pustular, and other forms of skin disease, the result of a depraved blood state.' They used it internally as tincture or fluid extract and externally as a lotion or ointment for skin conditions."
[2]
Western herbalism (contemporary practice)
- Alterative for chronic inflammatory skin conditions (psoriasis, eczema, acne), especially with hepatic involvement
- Choleretic and hepatic stimulant for sluggish liver function, poor fat digestion, and biliary insufficiency
- Bitter digestive tonic for functional dyspepsia and poor appetite
- Antimicrobial for GI infections, UTI, and topical skin infections
- Component in detoxification and elimination-support protocols
- Topical cream or ointment for psoriatic plaques (Mahonia cream/Relieva)
"Oregon Grape remains a staple alterative in modern Western herbal practice. Its reputation was substantially strengthened by the clinical research on topical Mahonia cream for psoriasis (Bernstein et al. 2006) and the landmark Stermitz et al. (2000) paper on berberine-efflux pump inhibitor synergy, which provided scientific validation for the traditional preference for whole-plant preparations over isolated constituents."
Modern Research
Topical Mahonia aquifolium cream for psoriasis
Double-blind, vehicle-controlled, bilateral comparison study evaluating the efficacy of a topical cream containing Mahonia aquifolium bark extract in patients with mild-to-moderate plaque psoriasis.
Findings: Mahonia aquifolium cream (Relieva) produced statistically significant improvement in PASI scores compared to vehicle control. Mean PASI improvement was significantly greater on the Mahonia-treated side than the control side. The cream was well tolerated with no serious adverse effects. The study supported the traditional use of Oregon Grape for psoriasis and provided Level I evidence for its efficacy in this indication.
Limitations: Bilateral comparison design (left vs right side of body) rather than parallel-group. Mild-to-moderate psoriasis only; efficacy in severe psoriasis not established. Single study; requires replication. Small sample size.
[5]
Large-scale observational study of Mahonia aquifolium for psoriasis
Multicenter observational study (n=443) evaluating a Mahonia aquifolium preparation in patients with psoriasis across multiple dermatology practices in Germany.
Findings: Significant improvement in psoriasis severity was observed across the study population. The preparation was rated as effective or very effective by the majority of both patients and physicians. Good tolerability was reported with minimal adverse effects. The large sample size provided robust safety data even though the open-label design limits efficacy conclusions.
Limitations: Open-label, uncontrolled observational study -- no placebo comparison. Homeopathic preparation rather than standardized herbal extract. Potential observer and reporting bias. No standardized outcome measures used across all centers.
[6]
Anti-psoriatic mechanism: anti-proliferative and anti-inflammatory activity
In vitro investigation of the mechanism of action of Mahonia aquifolium bark extract against psoriasis, examining effects on keratinocyte proliferation, lipoxygenase activity, and lipid peroxidation.
Findings: Mahonia aquifolium extract and its alkaloid constituents inhibited keratinocyte proliferation in a dose-dependent manner at concentrations achievable by topical application. The extract also inhibited 5-lipoxygenase and 12-lipoxygenase, enzymes that produce pro-inflammatory leukotrienes involved in psoriatic inflammation. Lipid peroxidation was also reduced. These findings provide a mechanistic basis for the clinical efficacy observed in psoriasis: Oregon Grape simultaneously addresses the hyperproliferation of keratinocytes and the inflammatory component of psoriatic plaques.
Limitations: In vitro study; direct extrapolation to in vivo clinical outcomes requires caution. Concentrations used may not fully reflect conditions in the skin during topical application. Single extract preparation tested.
[7]
Berberine synergy with 5'-methoxyhydnocarpin: efflux pump inhibition in Staphylococcus aureus
Landmark study published in PNAS demonstrating that Berberis species (including M. aquifolium) produce a compound, 5'-methoxyhydnocarpin (5'-MHC), that inhibits the NorA multidrug resistance efflux pump in Staphylococcus aureus, dramatically potentiating berberine's antimicrobial activity.
Findings: 5'-MHC, a flavonolignan isolated from Berberis species, potently inhibited the NorA efflux pump that S. aureus uses to expel berberine from its cells. In the presence of 5'-MHC, the minimum inhibitory concentration (MIC) of berberine against S. aureus was reduced by up to 16-fold. This demonstrated that the plant produces both an antimicrobial (berberine) and a resistance-blocking synergist (5'-MHC) together, explaining why whole-plant extracts are more effective than purified berberine. This paper became a landmark reference in herbal medicine research, frequently cited as proof-of-concept for the therapeutic superiority of whole-plant preparations over single isolated compounds.
Limitations: In vitro study using laboratory bacterial strains. Clinical validation in human skin or systemic infections not performed in this study. Specific to S. aureus NorA pump; generalizability to other organisms and resistance mechanisms requires further investigation.
[8]
Preparations & Dosage
Tincture
Strength: 1:5, 40% ethanol (dried root bark)
Use dried, finely chopped root bark. Standard maceration: 1:5 ratio in 40% ethanol (40-proof vodka or equivalent). Place chopped root bark in a glass jar, cover with menstruum, seal tightly, and macerate for 4-6 weeks with daily agitation. Press and filter through muslin and then filter paper. The finished tincture should be a deep golden-yellow to amber color. A pale tincture indicates poor-quality starting material or insufficient extraction.
2-4 mL (40-80 drops) three times daily, taken in a small amount of water 15-30 minutes before meals (to maximize the bitter reflex stimulation of digestive secretions)
Three times daily, preferably before meals
Short to medium-term courses (2-8 weeks) are typical. Oregon Grape is traditionally used in courses rather than indefinitely. Extended use beyond 2-3 months should be supervised. Rest periods (1-2 weeks off after each 4-6 week course) are recommended by some practitioners.
Not generally recommended for children under 12 due to the berberine content. Adolescents: half adult dose under practitioner supervision.
Tincture is the most common and versatile preparation for internal use. The alcohol efficiently extracts the alkaloids. Taking the tincture diluted in water allows the bitter taste to contact the tongue and activate the bitter reflex, which is desirable for digestive indications. For patients who cannot tolerate the bitter taste, capsules of powdered extract may be substituted, though the bitter reflex benefit is lost. The deep yellow color of the tincture is a quality indicator -- it reflects berberine and other protoberberine alkaloid content.
Decoction
Strength: 3-6 g dried root bark per 250 mL water
Use 1-2 teaspoons (3-6 g) of dried, chopped root bark per cup (250 mL) of cold water. Bring to a boil, reduce heat, and simmer gently for 15-20 minutes. Strain. The resulting decoction will be bright yellow and intensely bitter.
1/2 to 1 cup (125-250 mL) two to three times daily before meals
Two to three times daily before meals
2-8 week courses as described for tincture
Not recommended for children under 12
Decoction is the appropriate water-based extraction method for the woody root bark. Simple infusion (steeping) is insufficient for root bark material. Decoction is the traditional preparation method used by Indigenous peoples and Eclectic physicians. Can be combined with other bitter or hepatic herbs (dandelion root, burdock root, yellow dock) in compound formulas. The decoction can also be applied topically as a wash for skin conditions.
Standardized Extract
Strength: Variable; commercial products standardized to 5-10% total alkaloids or a specified berberine content. Relieva cream: 10% Mahonia aquifolium bark extract.
Commercially prepared standardized extracts of Mahonia aquifolium bark, typically standardized to berberine content or total alkaloid content. Used primarily in the manufacture of topical creams and capsule supplements. Standardization parameters vary by manufacturer.
Per manufacturer guidelines; typical oral dose of standardized extract is 250-500 mg two to three times daily. Topical cream: apply to affected areas twice daily.
Two to three times daily (oral); twice daily (topical)
Topical psoriasis use: minimum 4-8 week trial recommended based on clinical study duration
Not established
Standardized extracts are the form used in the published psoriasis clinical trials (Bernstein et al. 2006 used Relieva/Mahonia cream containing 10% Mahonia aquifolium bark extract). Topical cream application allows direct delivery of anti-proliferative and anti-inflammatory alkaloids to psoriatic skin at therapeutically effective local concentrations while minimizing systemic absorption. This is pharmacologically advantageous given berberine's low oral bioavailability.
topical-cream
Strength: 5-10% Mahonia aquifolium bark extract in cream base
Mahonia aquifolium bark extract incorporated into a cream or ointment base. Commercial products include Relieva (10% Mahonia aquifolium extract). For practitioner-compounded preparations: incorporate 5-10% tincture or fluid extract into a suitable cream base (aqueous cream, beeswax-oil base, or emulsifying ointment). Alternatively, prepare a strong decoction and use as a topical wash or compress.
Apply a thin layer to affected skin areas twice daily. Gently massage into plaques or affected areas. Wash hands after application unless hands are the treatment area.
Twice daily (morning and evening)
Minimum 4-8 weeks for psoriasis. May be used long-term for chronic conditions with periodic reassessment.
Safety not established for topical use in children. May be considered for adolescents under practitioner supervision.
Topical application is the best-supported route for psoriasis treatment and is the form used in the Bernstein et al. (2006) RCT. Advantages include direct delivery of anti-proliferative alkaloids (berberine, jatrorrhizine) to hyperproliferative keratinocytes, local anti-inflammatory action, and avoidance of the low oral bioavailability of berberine. The cream may cause mild, transient stinging or redness upon initial application; this typically resolves with continued use. The vivid yellow color of the extract may temporarily stain skin and clothing.
[5]
Safety & Interactions
Class 2b
Not to be used during lactation (AHPA Botanical Safety Handbook)
Contraindications
Berberine has demonstrated uterotonic activity (stimulation of uterine contractions) in animal models and may cross the placenta. Berberine has also shown potential to displace bilirubin from albumin binding sites, raising a theoretical risk of neonatal jaundice if used near term. The American Herbal Products Association (AHPA) classifies Mahonia aquifolium as class 2b: not to be used during pregnancy. This is a firm contraindication for internal use of therapeutic doses. Topical use over small skin areas in pregnancy has not been studied but is generally considered lower risk due to limited systemic absorption.
The choleretic action of berberine stimulates bile flow, which could potentially cause biliary colic or worsen obstruction in patients with gallstones blocking the bile duct. Oregon Grape root bark preparations should not be used in patients with known biliary obstruction or acute cholecystitis. In patients with known non-obstructive gallstones, use with caution under practitioner supervision.
Drug Interactions
| Drug / Class | Severity | Mechanism |
|---|---|---|
| CYP3A4 substrate medications (cyclosporine, certain statins, calcium channel blockers, many others) (CYP3A4 substrates) | moderate | Berberine inhibits cytochrome P450 3A4 (CYP3A4) enzyme activity in vitro and in pharmacokinetic studies. CYP3A4 is the most abundant drug-metabolizing enzyme and processes approximately 50% of pharmaceutical drugs. Inhibition of CYP3A4 by berberine can reduce the metabolic clearance of co-administered drugs, increasing their plasma concentrations and potentially causing adverse effects. |
| CYP2D6 substrate medications (codeine, certain antidepressants, certain beta-blockers) (CYP2D6 substrates) | moderate | Berberine has been shown to inhibit CYP2D6 in vitro. Inhibition could reduce the metabolism of CYP2D6 substrates, increasing their plasma levels. For prodrugs activated by CYP2D6 (e.g., codeine to morphine, tamoxifen to endoxifen), inhibition could reduce efficacy. |
| Metformin and other antidiabetic medications (Hypoglycemic agents) | minor | Berberine has demonstrated blood glucose-lowering effects through multiple mechanisms (enhanced insulin sensitivity, AMPK activation, inhibition of intestinal glucose absorption). Additive hypoglycemia is possible when combined with pharmaceutical antidiabetic agents. |
| Tetracycline antibiotics and other antibiotics (Antibiotics) | minor | Potential additive antimicrobial effects. Berberine may alter the pharmacokinetics of some antibiotics through CYP enzyme inhibition. Concurrent use could theoretically enhance antibiotic efficacy or increase side effects. |
Pregnancy & Lactation
Pregnancy
unsafe
Lactation
insufficient data
Oregon Grape is contraindicated in pregnancy (AHPA class 2b). Berberine demonstrates uterotonic activity and may displace bilirubin from albumin, posing a theoretical risk to the fetus/neonate. Breastfeeding: insufficient data on berberine excretion in breast milk. Internal use should be avoided during lactation as a precautionary measure. Topical use over limited skin areas during pregnancy and lactation is less concerning due to minimal systemic absorption, but has not been formally studied.
Adverse Effects
References
Monograph Sources
- [1] Hoffmann D. Medical Herbalism: The Science and Practice of Herbal Medicine. Healing Arts Press, Rochester, Vermont (2003)
- [2] Felter HW, Lloyd JU. King's American Dispensatory (Berberis aquifolium monograph). Ohio Valley Company, Cincinnati, Ohio (1898)
- [3] McGuffin M, Hobbs C, Upton R, Goldberg A. American Herbal Products Association's Botanical Safety Handbook. CRC Press, Boca Raton, FL (1997)
- [4] Moerman DE. Native American Ethnobotany. Timber Press, Portland, OR (1998)
Clinical Studies
- [5] Bernstein S, Donsky H, Ho Z, Feldman MD. Treatment of mild to moderate psoriasis with Relieva, a Mahonia aquifolium extract -- a double-blind, placebo-controlled study. Am J Ther (2006) ; 13 : 121-126 . DOI: 10.1097/01.mjt.0000140934.97110.0c . PMID: 16645428
- [6] Wiesenauer M, Ludtke R. Mahonia aquifolium in patients with psoriasis vulgaris -- an intraindividual study. Phytomedicine (1996) ; 3 : 231-235 . DOI: 10.1016/S0944-7113(96)80057-X
- [7] Muller K, Ziereis K. The antipsoriatic Mahonia aquifolium and its active constituents; I. Pro- and antioxidant properties and inhibition of 5-lipoxygenase. Planta Med (1994) ; 60 : 421-424 . DOI: 10.1055/s-2006-959522 . PMID: 7997468
- [8] Stermitz FR, Lorenz P, Tawara JN, Zenewicz LA, Lewis K. Synergy in a medicinal plant: antimicrobial action of berberine potentiated by 5'-methoxyhydnocarpin, a multidrug pump inhibitor. Proc Natl Acad Sci U S A (2000) ; 97 : 1433-1437 . DOI: 10.1073/pnas.030540597 . PMID: 10677479
Last updated: 2026-03-02 | Status: review
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