Oregon Grape

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Oregon Grape


Oregon Grape
© Steven Foster
Common names:
Botanical names:
Berberis aquifolium

Parts Used & 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.

What Are "Star" Ratings?

a7_3star   Reliable and relatively consistent scientific data showing a substantial health benefit.

a7_2star   Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.

a7_1star   For an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support.

Our proprietary “Star-Rating” system was developed to help you easily understand the amount of scientific support behind each supplement in relation to a specific health condition. While there is no way to predict whether a vitamin, mineral, or herb will successfully treat or prevent associated health conditions, our unique ratings tell you how well these supplements are understood by the medical community, and whether studies have found them to be effective for other people.

For over a decade, our team has combed through thousands of research articles published in reputable journals. To help you make educated decisions, and to better understand controversial or confusing supplements, our medical experts have digested the science into these three easy-to-follow ratings. We hope this provides you with a helpful resource to make informed decisions towards your health and well-being.

This supplement has been used in connection with the following health conditions:

Used for Amount Why
Chronic Candidiasis
Refer to label instructions 1 star   Oregon grape contains berberine, an alkaloid with antibiotic and antifungal activity that also been shown to help relieve the diarrhea seen in some people with chronic candidiasis.

1 star  Chronic Candidiasis

Berberine is an alkaloid found in various plants, including goldenseal, barberry, Oregon grape, and goldthread. Berberine exhibits a broad spectrum of antibiotic and antifungal activity in test tube, animal, and human studies.2 , 3 Berberine has shown effective antidiarrheal activity in a number of diarrheal diseases,4 , 5 , 6 and it may offer the same type of relief for the diarrhea seen in patients with chronic candidiasis. Doctors familiar with the use of berberine-containing herbs sometimes recommend taking 2 to 4 grams of the dried root (or bark) or 250 to 500 mg of an herbal extract three times a day. While isolated berberine has been studied, none of these herbs has been studied in humans with chronic candidiasis.

Used for Amount Why
Conjunctivitis and Blepharitis
Refer to label instructions 1 star   Oregon grape contains berberine, an antibacterial constituent that has been clinically studied for eye infections.

1 star  Conjunctivitis and Blepharitis

Goldenseal and Oregon grape contain the antibacterial constituent known as berberine. While topical use of berberine in eye drops has been clinically studied for eye infections,7 the use of the whole herbs has not been studied for conjunctivitis or blepharitis.

Used for Amount Why
Refer to label instructions 1 star   Berberine, a constituent of Oregon grape, has been shown to improve infectious diarrhea in some trials.

1 star  Diarrhea

Due to of its supposed antimicrobial activity, goldenseal has a long history of use for infectious diarrhea. Its major alkaloid, berberine (also found in barberry and Oregon grape), has been shown to improve infectious diarrhea in some double-blind trials.8 Negative studies have generally focused on people with cholera, while positive studies investigated viral diarrhea or diarrhea due to strains of E. coli. These studies generally used 400–500 mg berberine one to three times per day. Because of the low amount of berberine in most goldenseal products, it is unclear how effective the whole root or root extracts would be in treating diarrhea.

Used for Amount Why
Indigestion, Heartburn, and Low Stomach Acidity
Refer to label instructions 1 star   Oregon grape may stimulate digestion and relieve spasms in the intestinal tract.

1 star  Indigestion, Heartburn, and Low Stomach Acidity

Bitter herbs are thought to stimulate digestive function by increasing saliva production and promoting both stomach acid and digestive enzyme production.9 As a result, they are particularly used when there is low stomach acid but not in heartburn (where too much stomach acid could initially exacerbate the situation). These herbs literally taste bitter. Some examples of bitter herbs include greater celandine, wormwood, gentian,dandelion, blessed thistle, yarrow, devil’s claw, bitter orange, bitter melon, juniper, andrographis, prickly ash, and centaury.10. Bitters are generally taken either by mixing 1–3 ml tincture into water and sipping slowly 10–30 minutes before eating, or by making tea, which is also sipped slowly before eating.

Some bitters widely used in traditional medicine in North America include yarrow, yellow dock, goldenseal, Oregon grape, and vervain. Oregon grape’s European cousin barberry has also traditionally been used as a bitter. Animal studies indicate that yarrow, barberry, and Oregon grape, in addition to stimulating digestion like other bitters, may relieve spasms in the intestinal tract.11

Used for Amount Why
Refer to label instructions 1 star   Oregon grape is both immune supportive and antimicrobial.

1 star  Infection

Herbs that support a person’s immune system in the fight against microbes and directly attack microbes include the following: barberry, echinacea, elderberry, goldenseal, licorice, Oregon grape, osha, and wild indigo.

Used for Amount Why
Refer to label instructions 1 star   Berberine is derived from several plants, including Oregon grape. Studies have shown that berberine kills amoebae and can be used successfully to treat giardia infections.

1 star  Parasites

Berberine is derived from several plants, including barberry, Oregon grape, goldenseal, and goldthread (Coptis chinensis). Preliminary trials have shown that berberine can be used successfully to treat giardia infections.12 , 13 In addition, test tube studies show that berberine kills amoebae, although it is not known whether this effect occurs in humans.14 The amount required is approximately 200 mg three times per day for an adult—a level high enough to potentially cause side effects. Therefore, berberine should not be used without consulting a healthcare provider.

Used for Amount Why
Refer to label instructions 1 star   Oregon grape has been shown to be effective against moderate psoriasis and to reduce inflammation.

1 star  Psoriasis

An ointment containing Oregon grape (10% concentration) has been shown in a clinical trial to be mildly effective against moderate psoriasis but not more severe cases.15 Whole Oregon grape extracts were shown in one laboratory study to reduce inflammation often associated with psoriasis.16 In this study, isolated alkaloids from Oregon grape did not have this effect. This suggests that there are other active ingredients besides alkaloids in Oregon grape. Barberry, which is very similar to Oregon grape, is believed to have similar effects. An ointment, 10% of which contains Oregon grape or barberry extract, can be applied topically three times per day.

Used for Amount Why
Urinary Tract Infection
Refer to label instructions 1 star   Oregon grape contains berberine, an alkaloid that may prevent UTIs by inhibiting bacteria from adhering to the wall of the urinary bladder.

1 star  Urinary Tract Infection

Goldenseal is reputed to help treat many types of infections. It contains berberine, an alkaloid that may prevent UTIs by inhibiting bacteria from adhering to the wall of the urinary bladder.17 Goldenseal and other plants containing berberine (such as Oregon grape) may help in the treatment of UTIs. These herbs have not, however, been studied for the treatment of UTIs in humans.

Traditional Use (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.

How It Works

Common names:
Botanical names:
Berberis aquifolium

How It Works

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. 18 One of the ways berberine may ease diarrhea is by slowing the transit time in the intestine.19 Berberine inhibits the ability of bacteria to attach to human cells, which helps prevent infections, particularly in the throat, intestines, and urinary tract.20 These actions, coupled with berberine’s ability to enhance immune cell function,21 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.22 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.23 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 to Use It

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.


Common names:
Botanical names:
Berberis aquifolium

Interactions with Supplements, Foods, & Other Compounds

At the time of writing, there were no well-known interactions with this supplement.

Interactions with Medicines

Certain medicines interact with this supplement.

May Be Beneficial: Some medicines may increase the need for this supplement.
Avoid: Some medicines interact with this supplement, so they should not be taken together.
Check: Some interactions between this supplement and certain medicines require more explanation. Click the link to see details.

Note: The following list only includes the generic or class name of a medicine. To find a specific brand name, use the Medicines Index.

Avoid: Tetracycline
Check: Doxycycline

Side Effects

Common names:
Botanical names:
Berberis aquifolium

Side Effects

Oregon grape is thought to be safe in the recommended amounts. 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.24 For this reason, berberine-containing plants should be used with caution during pregnancy and breast-feeding.


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

2. Hahn FE, Ciak J. Berberine. Antibiotics 1976;3:577–88 [review].

3. Majahan VM, Sharma A, Rattan A. Antimycotic activity of berberine sulphate: an alkaloid from an Indian medicinal herb. Sabouraudia 1982;20:79–81.

4. Bhakat MP. Therapeutic trial of Berberine sulphate in non-specific gastroenteritis. Indian Med J 1974;68:19–23.

5. Kamat SA. Clinical trial with berberine hydrochloride for the control of diarrhoea in acute gastroenteritis. J Assoc Physicians India 1967;15:525–9.

6. Desai AB, Shah KM, Shah DM. Berberine in the treatment of diarrhoea. Indian Pediatr 1971;8:462–5.

7. Babbar OP, Chatwal VK, Ray IB, et al. Effect of berberine chloride eye drops on clinically positive trachoma patients. Ind J Med Res 1982;76:83–8.

8. Khin-Maung-U, Myo-Khin, Nyunt-Nyunt-Wai, et al. Clinical trial of berberine in acute watery diarrhoea. Br Med J 1985;291:1601–5.

9. Schulz V, Hänsel R, Tyler VE. Rational Phytotherapy: A Physician’s Guide to Herbal Medicine. 3rd ed, Berlin: Springer, 1998, 168–73.

10. Blumenthal M, Busse WR, Goldberg A, et al. (eds). The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. Austin: American Botanical Council and Boston: Integrative Medicine Communications, 1998, 425–6.

11. Tewari JP, Srivastava MC, Bajpai JL. Pharmacologic studies of Achillea millefolium Linn. Indian J Med Sci 1994;28(8):331–6.

12. Gupte S. Use of berberine in treatment of giardiasis. Am J Dis Child 1975;129:866.

13. Choudhry VP, Sabir M, Bhide VN. Berberine in giardiasis. Indian Pediatr 1972;9:143–6.

14. Kaneda Y, Torii M, Tanaka T, Aikawa M. In vitro effects of berberine sulphate on the growth and structure of Entamoeba histolytica, Giardia lamblia and Trichomonas vaginalis. Ann Trop Med Parasitol 1991;85:417–25.

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

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

17. Sun DX, Abraham SN, Beachey EH. Influence of berberine sulfate on synthesis and expression of pap fimbrial adhesin in uropathogenic Escherichia coli. Antimicrob Agents Chemother 1988;32:1274–7.

18. 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.

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

20. 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.

21. 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.

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

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

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

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