In an attempt to define the effects of Biphenyldimethyl dicarboxylate(DDB) on the lipid peroxidation, oxygen free radical scavenging enzymes activities and hepatic functions in ethanol-induced hepatotoxic rats, we studies malondialdehyde(MDA) level and the activities of catalse, superoxide dismutase(SOD), glutamic-oxaloacetic transaminase(GOT) and glutamic-pyruvic transaminase(GPT) in liver of the rats at 24, 48 and 72 hr after the injection of ethanol and DDB. Sprague-Dalwey albino rats weighing 250 to 280gm were injected intraperitoneally with ethanol(2.5 gm/kg ) only and ethanol plus DDB(300mg/kg ). The result obtained can be summarized as follows : 1) The group treated with ethanol showed significantly higher MDA level and lower catalase and SOD activities at 24, 48 and 72hr after the injection as compared with that of control group. 2) The group treated with ethanol showed significantly higher GOT and GPT activities at 24, 48 and 72hr after the injection as compared with that of control group. 3) The group treated with ethanol plus DDB showed significantly lower MDA level and higher catalase and SOD activities at 24, 48 and 72 hr after the injection as compared with that of ethanol group. 4) The group treated with ethanol plus DDB showed significantly lower GOT and GPT activities at 24, 48 and 72 hr after the injection as compared with that of ethanol group. These results suggest that the excessive oxygen free radicals resulting from the depression of the activities of catalase and superoxide dismutase is an important determinant in pathogenesis of ethanol-induced hepatotoxicity and DDB has antioxidant effects.