Yin Xie Pian is a special formula for help of chronic psoriasis and other skin problems and removes Blood Stagnation, clears Blood Heat and Toxic Heat. Chinese medicine believes that the pathogenesis of psoriasis is Blood Heat, Blood Stasis, and Blood Dryness. Heat in Blood causes bright red skin rash, Blood Stasis causes thick rash and Blood Dryness causes dry skin with scales.