PURPOSE: This study was carried out to determine the protective effects of vitamin C on the hepatotoxicity induced by radiation. MATERIALS AND METHODS: The Spraque Dawley rats were randomly divided into 3 groups; the control group, the radiation exposed group, and the radiation and vitamin C-treated group. SOD activity, catalase, malondialdehyde and liver enzymes were analyzed to assess the antioxidant effects of vitamin C. RESULTS: The increased level of malondialdehyde and the decreased catalase activity that were induced by radiation were improved after vitamin C but there was no statistical significance among three groups. The superoxide dismutase activity of the liver was increased by vitamin C, but there were no statistically significant differences between the vitamin C-treated group and the non vitamin C-treated group. The level of liver enzymes in sera such as glutamic oxaloacetic transaminase, glutamic pyruvic transaminase, lactate dehyrogenase and alkaline phosphatase were remarkably elevated by radiation. The levels of those enzymes were decreased in the vitamin C-treated group and statistical significance was noted for the GPT level (p<0.01). On the lectromicrographic findings, the hepatic cell destruction was considerably decreased in the vitamin C-treated group. CONCLUSION: Vitamin C is thought to be an effective antioxidant against the hepatotoxicity induced by radiation.