Cerebrospinal fluid (SF) in the quantity 5-7 ml from 26 multiple sclerosis patients was exposed to UV radiation with subsequent reinfusion. The assessment of clinical symptoms and immunological indices 7 days later showed that positive results (6 scores by Sipe scale) were achieved in 14 patients with cell abundance in the SF. The improvement was indicated by positive trends in pelvic functions, sensory and coordination disorders, normalization of the blood immunological picture. The responders exhibited elevated SF levels of B-lymphocytes, phagocytosing cells and IgM concentrations. High levels of IgG registered in 58% of the patients did not change. The only side effect was represented by short-term postpuncture syndrome in 4 patients with arterial hypotension. In 12 patients with progressive sclerosis the treatment was ineffective.