Scientific Names of Oregon Grape Root: Mahonia aquifolia (Lindl.)Don[Fam. Berberidaceae]

Root tea or tincture of Mahonia aquifolium L.

Traditional Usage:
– Antibacterial

– Antifungal

– Anti-protozoal

– Bladder Health Maintenance

– Diarrhea

– Digestive Disorders

– Diuretic

– Dysentry

– Expectorant

– Fever

– Genital Infections and Inflammation

– Respiratory Health Maintenance

– Skin Disorders

Oregon Grape, Mahonia aquifolium L. [Fam. Berberidaceae], also known as barberry, is a tall shrub found in the western regions of Canada and the United States. The bright yellow roots are very bitter and contain berberine and hydrastine, alkaloids also found in goldenseal (Hydrastis canadensis L.) that act as powerful antibiotics. Native Americans used the root tea to treat recurrent fevers, dysentery, to tonify, and to stop rectal hemorrhage. Oregon grape root partially works by stimulating bile and kidney secretions and improving digestion. The root’s antibacterial properties are also well documented and explain its successful use in treating skin and internal infections. Extracts are used as a blood-cleanser to treat acne, nausea, eczema, psoriasis and cold sores. The decoction acts as a digestive and liver tonic, which improves appetite and relieves rheumatic inflammation. There is no question that the alkaloids in Oregon grape root make it an effective antiseptic and treatment for diarrhea. Berberine is the most studied of the alkaloids and has been shown to possess fungicidal and antibacterial activities as well as activity against protozoa, e.g. Giardia lamblia, Trichomonas vaginalis and Entamoeba histolytica. In a non-controlled clinical study with children, berberine, in oral doses of 10 mg/kg/day for 10 days was found to be successful in treating giardiasis. It significantly inhibits the effects of enterotoxins of Vibrio cholerae and Escherichia coli. Intriguing possibilities also exist for the use of these alkaloids as agents against abnormal growths and the AIDS virus. Dr. Duke in The Green Pharmacy recommends Oregon grape root for treating psoriasis and notes that there are several anti-psoriasis compounds in Oregon grape root that are potent antioxidants. Antioxidants mop up free radicals that otherwise cause inflammation in diseases like psoriasis. Oregon grape root is also considered an anesthetic, expectorant, laxative, purgative, carminative, febribuge, sedative and diuretic.

Active Ingredients:
Oregon grape root contains: alkaloids berbamine, berberine, canadine, corypalmine, hydrastine, isocorydine, mahonine, and oxyacanthine, resin, and tannin. A recent study also reported the levels of the three quaternary alkaloids (berberine, palmatine, jatrorrhizine) in different parts of the genus Mahonia using high-performance capillary electrophoresis (HPCE). [Ji X, Li Y, Liu H, Yan Y, Li J. 2000. Determination of the alkaloid content in different parts of some Mahonia plants by HPCE. Pharm Acta Helv 2000 Apr; 74(4): 387-91].

Suggested Amount:
Oregon grape root tea is made by pouring 1 cup of boiling water over 2 grams of the drug, steeping for 5-10 minutes, then straining. The fluidextract dose is 10 to 20 drops diluted and taken every 3 or 4 hours as needed. The tincture dose is 20 to 40 drops per day. Based on goldenseal research, standardized alkaloid extracts of 10% (5% hydrastine) are recommended at 250 mg per day, not to be taken for periods longer than a week. Berberine was found effective for treating diarrhea among patients with enterotoxigenic E. coli and Vibrio cholerae with a single oral dose of 400 mg (Rabbani et al., 1987). At 5 mg/kg for six days berberine was found to be significantly better than placebo and as effective as metronidazole at 10 mg/kg (for the same duration) in treating children with giardia [Choudhry, V., M. Sabir and V. Bhide. 1972. “Berberine in giardiasis,” Indian J. Pediat. 9: 143-144; Rabbani, G., T. Butler, J. Knight, S. Sanyai and K. Alam. 1987. “Randomized controlled trial of berberine sulfate therapy for diarrhea due to enterotoxigenic Escherichia coli and Vibrio cholerae,” J. Infect Dis. 155: 979-984].

Drug Interactions:
Prolonged use of Oregon grape root may interfere with vitamin B absorption, based on goldenseal research.

Oregon grape root is contraindicated during pregnancy and lactation. Berberine and the other Hydrastis alkaloids can stimulate the uterus and should not be used during pregnancy as it may induce abortion. Oregon grape root may also be problematic for those suffering from high blood pressure, heart disease, diabetes, glaucoma or with a history of stroke, based on contraindications of goldenseal.

Side Effects:
Oregon grape root can cause intense pain when used to treat eye and skin infections. If taken in large quantities, it has been reported to cause acute and even fatal poisoning. Injections of the drug may produce hyper-pigmentation. At recommended dosages, berberine and berberine-containing plants are considered to be nontoxic. High doses of hydrastine, however, are reported to cause exaggerated reflexes, convulsions, paralysis and death from respiratory failure. Goldenseal Research: At doses of 2-3 grams, goldenseal can lower heartbeat and at higher doses it can be paralysing to the central nervous system. Goldenseal (and therefore possibly Oregon grape root) extracts are known to cause severe ulceration and therefore cannot be recommended as a douche.


Bezakova L, Misik V, Malekova L, Svajdlenka E, Kostalova D. 1996. Lipoxygenase inhibition and antioxidant properties of bisbenzylisoqunoline alkaloids isolated from Mahonia aquifolium. Pharmazie 1996 Oct; 51(10): 758-61.

Duke JA. 1985. Oregon Grape. In Handbook of Medicinal Herbs. CRC Press, Boca Raton, FL, p. 287-288

Kaneda, Y., X and Y. 1991. “In vitro effects of berberine sulfate on the growth and structure of Entamoeba histolytica, Giardia lamblia and Trichomonas vaginalis,” Annals Trop. Med. Parasit. 85: 417-425.

Muller K, Ziereis K. 1994. The antipsoriatic Mahonia aquifolium and its active constituents; I. Pro- and antioxidant properties and inhibition of 5-lipoxygenase. Planta Med 1994 Oct; 60(5): 421-4.

Sotnikova R, Kettmann V, Kostalova D, Taborska E. 1997. Relaxant properties of some aporphine alkaloids from Mahonia aquifolium. Methods Find Exp Clin Pharmacol 1997 Nov; 19(9): 589-97.