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Oregon Grape

Oregon Grape

Botanical Description & Habitat

Mahonia aquifolium


Common Names
California barberry
Holly mahonia
Rocky Mountain grape
Trailing mahonia

Mountain areas on wooded slopes below 7000 feet throughout the Western part of North America.

Medicinal Parts
The rootstock and roots

Historical Properties & Uses

Oregon grape is used almost exactly like other Berberis species and goldenseal (Hydrastis canadensis), as an alterative, antibiotic, diuretic, laxative and tonic. It is commonly used internally to detoxify the blood in an effort to cure skin problems. Also occasionally used as a treatment for rheumatism.

In homeopathy, Oregon grape is used as a tincture for skin diseases, like acne, eczema, herpes and psoriasis.

Method of Action

Oregon Grape is a good Antibiotic and Cholagogue
Oregon grape contains berberine alkaloids, including berberine, berbamine and oxyacanthine, stimulating the gut and the uterus, and are somewhat strong antibiotics.

The British Herbal Pharmacopoeia recognizes Oregon grape as an anti-catarrhal, antiemetic, mild cholagogue and laxative, for use in the treatment of cutaneous disease, gastritis, and leucorrhea, with specific indications of psoriasis, eczema, catarrhal gastritis with cholecystitis.

Combined with burdock root or yellow dock root in skin conditions; with chamomile, acorus and culver's root in stomach and gallbladder disease.

Alkaloids in the various species of Oregon grape root:









Drug Interactions & Precautions

Known Interactions
Oregon grape, insofar as its diuretic action increases the renal excretion of sodium and chloride, may potentiate the hyperglycemic and hyperuremic effects of glucose elevating agents.

Oregon grape, due to its cathartic activity, may potentiate anticoagulant therapy by reducing absorption of vitamin K from the gut. It may also inhibit absorption of dextrose from the intestines.

This cathartic may increase intestinal transit time of digitalis glycosides, inhibit their absorption and cardiac action. But cathartic-induced hypokalmia increases toxicity and potency of absorbed digitalis. Cathartic-induced hypokalemia potentiates muscle relaxants.

In addition to the specific interactions listed, the cathartic action of oregon grapes tend to hasten the passage of all oral medications through the gut and thereby inhibit their action.

In sub-laxative and sub-emetic doses this herb should have no drug interactions. At higher doses, interactions similar to those involving diuretics and cathartics may occur.

Possible Interactions
The use of diuretics may require dosage adjustments of antidiabetic drugs.

Laxative-induced diarrhea may result in decreased absorption of isoniazid the same is true with sulfisoxazole, but it appears to be a clinically unimportant interaction effect.

There is evidence combining bactericidal and bacteriostatic agents will lower the effectiveness of the '-static' variety. How this finding applies to herbal antibiotics is not known.

Laxative induced increased speed of intestinal emptying may result in decreased absorption of vitamin K and/or anticoagulants.

Safety Factors & Toxicity

Oregon grape is nontoxic in therapeutic dosages.

Preparation & Administration

Use three times daily

Use 1-2g of dried root

Liquid Extract
Use 1-2ml of 1:1 in 25% alcohol

Note: This Herbal Preparation information is a summary of data from books and articles by various authors. It is not intended to replace the advice or attention of health care professionals.


Braun, H. & Frohne, D. Heilplanzen-Lexikon Fuer Aerzte und Apotheker. Gustav Fisher Verlag, Stuttgart, New York, 1987.

British Herbal Pharmacopoeia, British Herbal Medicine Association, 1983.

Duke, J.A. CRC Handbook of Medicinal Herbs, CRC Press, Inc., Boca Raton, Florida, 1985.

Mowrey, Daniel B., Ph.D. Exper. Psych., Brigham Young University. Director of Nebo Institute of Herbal Sciences. Director of Behavior Change Agent Training Institute. Director of Research, Nova Corp.

Schauenberg, P. & Paris, F. Guide to Medicinal Plants, Keats Publishing, Inc., New Canaan, Connecticut, 1977.


Mahonia aquifolium

? Southwest School of Botanical Medicine