A comparative study of the clinico-immunological efficacy of steroid hormones and thymus drugs in 50 patients with unspecific ulcerative colitis of different activity grades revealed that their efficacy was not similar at different phases of the disease and depended on the activity of the inflammatory process. Corticosteroids were more effective in inflammatory-destructive changes in the mucosa of the large intestine while in mild inflammation with prevalence of ulcerative-reparative processes, immunomodulators (thymalin) are preferred.