The effect of plasmapheresis and its modification with ozonation of returned red blood cell suspension on the course of the cutaneous process and on some immunological parameters was investigated in patients with disseminated psoriasis. Its clinical picture, the parameters of humoral immunity and a phagocytic process, and the serum levels of cytokines were studied over time. Patients with an exacerbation of disseminated psoriasis were observed to have elevated levels of tumor necrosis factor-α, interlekin-2, circulating immune complexes, immunoglobulins M and A, and enhanced neutrophil defense activity. There was a relationship between the study parameters to the clinical features of the disease, gender, age, and a family history.