Abstract: Ninety-eight patients with psoriasis vulgaris were treated with lnjectio Cinobufocini (Chinese toad element) intramuscularly 2-4ml, everyday for six weeks. 19 cases (19.4%) were cured, 26 cases (26.5%) nearly cured, 14 cases (14.3%) markedly improved, 17 cases (17.3%) improved and 22 cases (22.4%) failed. Effective rate was 77.6%. 31 cases were followed up for 1-6 months after the treatment, 16% of them relapsed and 25.8% continued to improve. There were no obvious side reactions. The authors used two kinds of psoriatic animal models, mouse tail scale epidermis and mouse vaginal epithelium in estrogen phase, to study the therapeutic mechanism of the Cinobufocin. The results suggest that Cinobufocin could, on one hand, promote the formation of grams.lar layer anal, on the other, suppress the mitosis of mouse vaginal epithelium, thus correcting the pathologic process of parakeratosis and hypcrpiasia of the psoriatic epidermis. It might partially explain the effective mechanism of Cinobufocin.