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Oregon Grape

Botanical name: Berberis aquifolium


© Steven Foster

Parts used and where grown

Oregon grape is an evergreen shrub which grows throughout the American northwest. It is somewhat misnamed, as the fruit are not actually grapes. It is, however, grown in Oregon (it is the official state flower). Oregon grape is a close relative of barberry (Berberis vulgaris), and shares many common uses and constituents. The root is used medicinally.

Oregon grape has been used in connection with the following conditions (refer to the individual health concern for complete information):

Science Ratings Health Concerns

Chronic candidiasis





Poor digestion


Urinary tract infections

3Stars Reliable and relatively consistent scientific data showing a substantial health benefit.
2Stars Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.
1Star For an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support and/or minimal health benefit.

Historical or traditional use (may or may not be supported by scientific studies)

Before European colonists arrived, the indigenous peoples of North America treated all manner of complaints with Oregon grape.1 The berries were used for poor appetite. A tea made from the root was used to treat jaundice, arthritis, diarrhea, fever, and many other health problems.

Active constituents

Alkaloids, including berberine, berbamine, canadine, and hydrastine, may account for the activity of Oregon grape. Isolated berberine has been shown to effectively treat diarrhea in patients infected with E. coli.2 One of the ways berberine may ease diarrhea is by slowing the transit time in the intestine.3 Berberine inhibits the ability of bacteria to attach to human cells, which helps prevent infections, particularly in the throat, intestines, and urinary tract.4 These actions, coupled with berberine’s ability to enhance immune cell function,5 make Oregon grape possibly useful for mild infections although clinical trials are lacking on the whole root.

In one clinical trial, an ointment of Oregon grape was found to be mildly effective for reducing skin irritation, inflammation and itching in people with mild to moderate psoriasis.6 Whole Oregon grape extracts were shown in one pharmacological study to reduce inflammation (often associated with psoriasis) and stimulate the white blood cells known as macrophages.7 In this study, isolated alkaloids from Oregon grape did not have these actions. This suggests that something besides alkaloids are important to the properties of Oregon grape responsible for reducing inflammation.

The bitter-tasting compounds as well as the alkaloids in Oregon grape root are thought to stimulate digestive function.

How much is usually taken?

A tea can be prepared by boiling 1–3 teaspoons (5–15 grams) of chopped roots in 2 cups (500 ml) of water for fifteen minutes. After straining and cooling, 3 cups (750 ml) can be taken per day. Tincture, 1/2–3/4 teaspoon (3 ml) three times per day, can be used. Since berberine is not well absorbed, Oregon grape root might not provide adequate amounts of this compound to treat significant systemic infections. A physician should be consulted in the case of infection before attempting to use Oregon grape. An ointment made with 10% Oregon grape extract applied three or more times daily may be useful for psoriasis.

Are there any side effects or interactions?

Oregon grape is thought to be safe in the amounts indicated above. Long-term (more than two to three weeks) internal use is not recommended. Berberine alone has been reported to interfere with normal bilirubin metabolism in infants, raising a concern that it might worsen jaundice.8 For this reason, berberine-containing plants should be used with caution during pregnancy and breast-feeding.

Are there any drug interactions?
Certain medicines may interact with Oregon grape. Refer to drug interactions for a list of those medicines.


1. Duke JA. CRC Handbook of Medicinal Herbs. Boca Raton, FL: CRC Press, 1985, 287–8.

2. Rabbani GH, Butler T, Knight J, et al. Randomized controlled trial of berberine sulfate therapy for diarrhea due to enterotoxigenic Escherichia coli and Vibrio cholerae. J Infect Dis 1987;155:979–84.

3. Eaker EY, Sninsky CA. Effect of berberine on myoelectric activity and transit of the small intestine in rats. Gastroenterol 1989;96:1506–13.

4. Sun D, Courtney HS, Beachey EH. Berberine sulfate blocks adherence of Streptococcus pyogenes to epithelial cells, fibronectin, and hexadecane. Antimicrob Agents Chemother 1988;32:1370–4.

5. Kumazawa Y, Itagaki A, Fukumoto M, et al. Activation of peritoneal macrophages by berberine-type alkaloids in terms of induction of cytostatic activity. Int J Immunopharmacol 1984;6:587–92.

6. Wiesenauer M, Lüdtke R. Mahonia aquifolium in patients with psoriasis vulgaris—an intraindividual study. Phytomedicine 1996;3:231–5.

7. Galle K, Müller-Jakic B, Proebstle A, et al. Analytical and pharmacological studies on Mahonia aquifolium. Phytomedicine 1994;1:59–62.

8. Chan E. Displacement of bilirubin from albumin by berberine. Biol Neonate 1993;63:201–8.

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