In the present study, the comparison of liver damage in carbon tetrachloride (CCl$_4$)-treated rats with that those pretreated with ethanol and an effect of liver injury on the serum and liver xanthine oxidase (XOD) activity were evaluated. The increasing rate of liver weight per body wt., the levels of serum alanine aminotransferase, and the decreasing rate of hepatic glucose-6-phosphatase activity and the protein contents in the liver cell were higher in carbon tetrachloride-treated animals pretreated with ethanol than the carbon tetrachloride-treated group. Especially, the histopathological findings also showed more severe liver damage in the ethanol-pretreated rats than the rats treated with carbon tetrachloride only. In such a experimental condition the xanthine oxidase activity of serum and liver both of carbon tetrachloride-treated rats and those pretreated with ethanol were higher than that of each control group. And the increasing rate of xanthine oxidase enzyme activity to the control group was higher in carbon tetrachloride-treated group pretreated with ethanol than those treated with CCl$_4$. In addition, the heptic uricase activity and the serum levels of uric acid were more increased in carbon tetrachloride-treated group pretreated with ethanol than those in the CCl$_4$-treated rats. On the other hand, there were no statistical differences in hepatic catalase and glutathione S-transferase activities between the CCl$_4$-treated rats and those pretreated with ethanol. In conclusion, it is assumed that the more severe liver damage in ethanol pretreated rats would be due to oxygen free radical produced by the xanthine oxidase system.