The lipid peroxidation level and the antioxidant system status have been studied by the amount of alpha-tocopherol and the antioxidant activity of homogenates in the brain, liver, heart and somatic muscle of rats given Vitamins A and E, as physiological additives, before and after gamma-irradiation. It has been shown that a new dynamic balance between the parameters under study is rapidly set up after irradiation, which represents a mechanism of rapid adaptation. The radioprotective effect of alpha-tocopherol is more pronounced than that of Vitamin A (particularly in the brain). In most cases, Vitamin A produces, upon irradiation, an unfavourable effect on antioxidative homeostasis.