The immunomodulatory activity of peptide drugs i.e. tinrostim (dosage form) prepared of squid optical ganglia and pharmacopoeia thymain was studied. Tinrostim showed a stimulating effect on the humoral and cellular nimmune responses when administered parenterally in experimental animals, as well as on the phagocytic activity of neutrophils, comparable to the effect of thymalin. It was demonstrated that both the peptide drugs increased the production of pro-(TNFa, IL-1) and antiinflammatory (IL- 10) cytokines in the culture of intact cells of peripheral blood in vitro. It is essential that when tinrostim was used in 10-fold different doses (0.005 mg / kg and 0.05 mg /kg) in mice, the effect of the lower dose was comparable to the effect of the higher dose.