Psoriasis and Oregon Grape

The roots and bark of the shrub Mahonia aquifolium (also called Oregon grape) have traditionally been used both orally and topically to treat skin problems, as well as other conditions. A few studies indicate that a topical ointment made from Oregon grape might be effective for treating psoriasis.

Laboratory research suggests Oregon grape has some effects at the cellular level that might be helpful in psoriasis, such as slowing the rate of abnormal cell growth and reducing inflammation.^14,15

Read more details about Oregon Grape.

Evidence from two double-blind, placebo-controlled trials and one comparative trial suggest that cream made from the herb Oregon grape may help reduce symptoms of psoriasis. Oregon grape appears to be less effective but have fewer side effects than standard medications.

In a double-blind study published in 2006, 200 people were given either a cream containing 10% Oregon grape extract or placebo twice a day for 3 months.²⁷ The results indicate that the people using Oregon grape experienced greater benefits than those in the placebo group, and the difference was statistically significant. The treatment was well tolerated; although, it caused rash or burning sensation in a few people.

Benefits were also seen in a double-blind, placebo-controlled study of 82 people with psoriasis.¹¹ However, the study design had a significant flaw: the treatment salve was darker in color than the placebo, possibly allowing participants to guess which was which.

Another study found that dithranol, a conventional drug used to treat psoriasis symptoms, was more effective than Oregon grape.¹² Regrettably, the authors fail to state whether this study was double-blind. Forty-nine participants applied one treatment to their left side and the other to their right for 4 weeks. Skin biopsies were then analyzed and compared with samples taken at the beginning of the study. The physicians evaluating changes in skin tissue were unaware which treatments had been used on the samples. Greater improvements were seen in the dithranol group.

A large open study in which 443 participants with psoriasis used Oregon grape topically for 12 weeks found the herb to be helpful for 73.7% of the group.¹³ Without a placebo group, it's not possible to know whether Oregon grape was truly responsible for the improvement seen, but the trial does help to establish the herb's safety and tolerability.

Topical ointments or creams containing 10% Oregon grape extract are generally applied 3 times daily to the affected areas.

• Herbalist
• Integrative dermatologist
• Naturopath

Safety Issues

Oregon grape appears to be safe when used as directed. In the large open study described above, only 5 of the 443 participants reported side effects of burning, redness, and itching. ¹ However, because Oregon grape contains berberine, which has been reported to cause uterine contractions and to increase levels of bilirubin, oral consumption of Oregon grape should be avoided by pregnant women. ² Safety in young children, nursing women, or people with severe liver or kidney disease has not been established.

There is an additional concern regarding the berberine content of Oregon grape. One study found that berberine impairs metabolism of the drug cyclosporine, thereby raising its levels. ³ This could potentially cause toxicity.

1. Gieler U, von der Weth A, Heger M. Mahonia aquifolium—a new type of topical treatment for psoriasis. J Dermatol Treat. 1995;6:31-34.
2. deSmet PAGM, et al. (eds). Adverse effects of herbal drugs. New York, NY: Springer-Verlag;1992:97-104.
3. Wu X, Li Q, Xin H, Yu A, Zhong M. Effects of berberine on the blood concentration of cyclosporin A in renal transplanted recipients: clinical and pharmacokinetic study. Eur J Clin Pharmacol. 61(8):567-72.

11. Wiesenauer M, Ldtke R. Mahonia aquifolium in patients with Psoriasis vulgaris - an intraindividual study. Phytomedicine. 1996;3:231-235.
12. Augustin M, Andrees U, Grimme H, et al. Effects of Mahonia aquifolium ointment on the expression of adhesion, proliferation, and activation markers in the skin of patients with psoriasis. Forsch Komplementrmed. 1999;6(suppl 2):19-21.
13. Gieler U, von der Weth A, Heger M. Mahonia aquifolium - a new type of topical treatment for psoriasis. J Dermatol Treat. 1995;6:31-34.
14. Galle K, Mller-Jakic B, Proebstle A, et al. Analytical and pharmacological studies on Mahonia aquifolium. Phytomedicine. 1994;1:59-62.
15. 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.
27. Bernstein S, Donsky H, Gulliver W, et al. 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.