158 patients with different forms of psoriasis were examined for the content of kallikrein and kallikreinogen in blood plasma and treated by different preparations including andecalin and dilminal-D. Changes in the kallikrein-kinin system may play a role in the development of psoriasis. The aim of this study was to investigate the relationship of changes in the kallikrein-kinin system induced by andecalin and dilminal-D and the clinical course of psoriasis. Determination of kallikrein and kallikreinogen content in blood plasma was made according to the methods of Paskhina and Krynskaya. Almost all psoriatic patients showed high kallikrein and kallikreinogen levels in blood plasma. We conclude that changes in the kallikrein-kinin system are involved in the pathogenesis of psoriasis. Andecalin and dilminal-D preparations resulted in a marked amelioration of psoriasis.