- Oregon grape (Mahonia aquifolium, Berberis aquifolium) is native to the west coast of North America, from British Columbia to northern California. It has yellow flowers, purple berries, and leathery leaves that resemble holly. It is not related to grape; however, the name Oregon grape originated from the purple clusters of berries that resemble grapes. It is a close relative of barberry (Berberis vulgaris).
- The rhizome, root, and bark, which are odorless and bitter, are collected in autumn to be used medicinally. Native Americans have traditionally used Oregon grape to treat various ailments, including digestive problems and inflammatory skin conditions. Studies in humans have shown that it may be effective against atopic dermatitis and psoriasis. Substances found in Oregon grape have been studied for their anticancer and antibacterial effects, although these uses are not well-studied in humans.
- Oregon grape is also used in food, landscaping, and dyes.