Objective To study the therapeutic effect of Jiedu Quyu Formula （Formula for Removing Toxins and Blood Stasis） on psoriasis vulgaris of progressive stage and its mechanism. Methods The 70 patients of progressive psoriasis vulgaris were randomized into treatment group （35 cases）

treated by Jiedu Quyu Formula

and control group （35 cases）

treated by Compound Qingdai Capsule. Healthy control group was of 30 healthy subjects. The contents of plasma endothelin （ET） were determined before and after treatment respectively

and the therapeutic effect of both treated groups were observed. Results After treatment

the psoriasis area and severity index （PASI） of both treated groups were significantly decreased in comparison with before treatment （P<0.05）. After two treatment coures

PASI of the treatment group was significantly lower than that of the control group （P<0.05）. In treatment group

the remarkable effective rate was 74.3%

and in control group

it was 51.4%. The difference was significant （P<0.05）. There found an obvious decrease of content of ET in treatment group as well （P<0.01）. Conclusion Jiedu Quyu Formula is effective for psoriasis vulgaris of progressive stage and functions to decrease the content of ET.