Mahonia aquifolium in patients with psoriasis vulgaris - an intraindividual study.

Psoriasis vulgaris is a skin disease with a multi-factorial genesis where no causal treatment is known. Based on our own pilot studies, we set up a randomized, placebo-controlled clinical trial to evaluate the efficacy and safety of Mahonia aquifolium bark extract in psoriasis patients. From autumn 1990 to spring 1992 we treated 82 patients of all severity gradings, recruited by 22 family physicians. Patients were told to apply two types of ointment (verum/ placebo) one to the left side of their body the other to the right. After an average treatment period of four weeks, patients as well as physicians assessed the therapy's success on a three-level ordinal rating scale. Statistically significant differences (α = 5%) could be found for patients' but not for physicians' assessments. Additional analyses show that treatment differences are not significantly masked by parallel antipsoriatic therapies. Adverse drug reactions, such as itching and burning sensations and "allergic reactions,' occured in four patients. Therefore, we regard Mahonia aquifolium bark extract as a potent and safe therapy of moderately severe cases of psoriasis vulgaris.