The Chinese medicinal, Radix Angelicae Dahuricae (Bai Zhi), is commonly used for the treatment of psoriasis. I commonly add this herb to a herbal formula when a patient complains of a strong itch. My dermatology teacher, Mazin Al Khafaji, explained to me that Bai Zhi actually slows down the growth of psoriatic skin cells, which are reproducing every 3-5 days instead of the normal 30 days for healthy normal skin. In a study published in the Chinese Journal of Dermatology (Zhong Hua Pi Fu Ke Xue Za Zhi), Bai Zhi was shown to be 94.4% effective in the treatment of Psoriasis. The study treated 159 psoriasis patients with Bai Zhi in different preperations, including including capsules and decoction.