Objective: To study the impact of Tuiyin tang on expression level of neutrophil elastase(NE) in peripheral blood of psoriasis vulgaris. Method: Competing-ELISA was used to detect peripheral blood levels of NE in 40 cases of psoriasis vulgaris before and after treatment with Tuiyin tang

and those of the control group were also detected. Result: Forty cases of psoriasis vulgaris showed that serum level of NE was (16.90±3.30)mg·L-1

and normal control group was (3.67±1.49) mg·L-1

the difference was statistically significant (P<0.01). After Tuiyin tang treatment for 12 weeks

NE level in psoriasis patients was significantly decreased (9.16±2.43) mg·L-1

which had statistically significant difference compared with before treatment(P<0.01). Conclusion: Tuiyin tang can reduce the serum level of NE in patients with psoriasis vulgaris

and NE may be involved in the pathogenesis of psoriasis.