Abstract: Neutrophil (PMN) chemotaxis in patients with psoriasis vulgaris was assessed using in vitro improved filter membrane technique.The micro-pore filter menbrane used was made in Shanghai, China. Adventages of this method were simple and convenient, and require a small amount of blood. 105 patients with psoriasis and 30 healthy control subjects were studied. The results obtained from both groups suggested that the PMN chemotaxis was related to the stage of psoriasis, increased significantly in patients in the progressive stage, and no significant difference in patients in the regressive stage and patients treated with Bi molant (AT-1727).