Barberry is a bush that grows wild in Europe and North America. It is closely related to Oregon grape ( Berberis aquifolium). The root, stem, bark, and fruit of barberry are all used medicinally. Barberry was traditionally used as a treatment for digestive problems, including constipation, diarrhea, dyspepsia (stomach upset), heartburn, and loss of appetite. It was said to work by increasing the flow of bile, and on this basis it has also been used for liver and gallbladder problems. Topical preparations of barberry have been recommended for the treatment of eczema, psoriasis, and minor wounds.
Barberry is traditionally used at a dose of 2 grams three times daily, or an equivalent amount in extract form. For treatment of psoriasis and other skin conditions, barberry is used in the form of a 10% cream, applied to the skin three times daily.