Investigation of therapeutic effectiveness of cortexin in chronic alcohol encephalopathy and chronic alcohol polyneuropathy was conducted in an open randomized study. The aim of the study was to compare these disorders with diabetic and professional polyneuropathy. Cortexin was prescribed in dose 10 mg/d intramuscular during 10 days, along with standard therapy. The group of patients consisted of 15 people with alcohol disorders, 15 people with diabetic polyneuropathy and 15 people with professional polyneuropathy. The control group included 15 patients with alcohol disorders who did not receive cortexin. Encephalography (EEG) and electroneuromyography (ENMG) were used in addition to the clinical examination. Cortexin had the positive effect on clinical symptoms, EEG and ENMG. The drug was well-tolerated, no side-effects were observed.