Albino rats were treated with aqueous vitamin C solution and vitamin E solution dissolved in olive oil at two concentrations, 100 and 300 mg/kg/day, for 6 months. Some of the animals were then subjected to whole-body irradiation. Chromosomal aberrations and mitotic activity in non-irradiated and irradiated groups were recorded. Both vitamins were found to be non-mutagenic. Vitamin C exerted a radioprotective effect but vitamin E was not radioprotective and it suppressed the radioprotection otherwise produced by olive oil.