The data on the effect of the succinate-containing antioxidant mexidol on the adaptation abilities of patients with chronic brain ischemia are presented. We studied 98 patients with discirculatory encephalopathy of I, II and III stages. A set of indices for psychoemotional status, functional state of the brain, autonomic status, nonspecific stability to hypoxia, adaptive reactions of the blood system and status of antioxidant defense have been used to evaluate adaptive abilities of the body. It has been shown that the introduction of the antioxidant in the treatment set strengthens the effects of basic treatment by increasing adaptive reserves of the body in stages I and II of disease that is related with the realization of reactions of urgent adaptation. The introduction of mexidol in the treatment set increases the frequency of favorable outcomes after one year of follow-up.