43 patients and 20 healthy children, aged 11-15, were examined. Increased contents of primary, secondary, intermediary and final products of lipid peroxidation (LPO) in serum lipids as well as an intensified antioxidant activity were registered in children with erosive gastroduodenitis. Ventramine, when used in the treatment of erosive gastroduodenitis in children, arrests rapidly the clinical signs of the disease and normalizes LPO.