Abstract The present study was conducted to investigate the short-term impact of the exogenous antioxidant α-tocopherol [Vitamin E] in preventing the radiation-induced liver injury. Fifty-six Wistar rats received intraperitoneally α-tocopherol [25 mg/kg] or placebo at 12 hs and 1 h before local exposure of the abdomen to a single 11 Gy dose of ionizing radiation from a 60Co source, or sham-radiation. Two and 6 hs later, the degree of lipid peroxidation [hepatic tissue MDA] as well as the liver GSH levels, as a measure of the endogenous antioxidant defense, were recorded. It was found that α-tocopherol as pretreatment led to a reduction of MDA after liver irradiation in relation to placebo-treated rats. Similarly, it was found to contribute to a minor reduction of liver GSH levels and the early achievement of nearly normal values in relation to placebo-treated rats. We conclude that the prophylactic administration of α-tocopherol exerts an intense antioxidant action by reducing liver lipid peroxidation and maintaining the endogenous liver antioxidant defense against radiation-induced injury.