Our investigation is an attempt to confirm the probability to use the cycloferon for the extracorporeal immunopharmacotherapy. For this aim the leukocytes, obtained from 5 ml of venous blood of 17 healthy individuals, were stimulated by different doses of cycloferon during 1 h and after 24 h we determined interferon-alpha (IFN-alpha) concentration, tumor-necrosis factor-alpha (TNF-alpha), intreleukin-4 (IL-4) in the supernatant of stimulated and intact cells. Obtained results suggest that incubation of the blood leukocytes with cycloferon lead to the evident increase of IFN-alpha production. Dose-dependent effect of the stimulation is observed in the range of the cycloferon concentrations from 50 mg/l to 200 mg/l. Cycloferon poorly induces IFN-alpha production by leukocytes (50-150 ng/l) in comparison with phytohemagglutinin and other non-specific or bacterial stimulators. However, such quantity of IFN-alpha may be adequate to stimulate immune response, if the patient is reinfused by large amount of the autologous leukocytes, activated by cycloferon, isolated from 100-400 ml blood. The influence of cycloferon is less evident in the production of TNF-alpha, IFN-gamma and IL-4 by leukocytes at the range of the studied doses. It should be noted that the individual peculiarities of donor leukocyte reaction may be seen in response to the cycloferon. Obtained results suggest the principal possibility to use autologous leukocytes extracorporeally activated by IFN inductors for the immunotherapy.