Experiments on outbred albino rats showed that tactivin (thymic polypeptide preparation) reduced functional disturbances in active avoidance reaction induced by extra electric current exposure violating the established relationships between the stimuli, reaction, and its result. The preparation provided high level of avoidance reaction after its violation. New effects of immunocorrective agent tactivin were detected. It not only restored the disordered immunological parameters, but also exhibited a pronounced effect on the higher integrative functions of the brain and produced an antistress effect.