The effect of onion juice on ethanol -induced lipid peroxidation were studied were studied in rats. The contents of thiobarbituric acid (TBA) -reactants increased significantly in liver thanol(4ml/kg/day) administered -rats. The activities of serum alanine aminotransferase and alkaline phosphatase increased by ethanol administration compared with control group, but alterations of antioxidant enzymes activities in liver of ethanol administered rats were not significant vs control group. The glutathione contents in liver decreased by ethanol , whereas the glutathione level increased in ethanol and onion juice group compared with ethanol group. The contents of hepatic TBA-reactants and serum aminotrasnferase activity in ethanol group were reduced by onion juice administration. In these results, increased hepatic TBA-reactants of liver in ethanol group might be due to decreased glutathione contents in liver. Reduced glutathione (GSH) plays an important roles in the liver in several detoxification and the reduction of lipid peroxides. So the protective effects of onion juice on ethanol-induced increment of TBA-reactants may be due to the increament of lgutathions content. The glutathione depletion by ethanol was an important factor of ethanol-induced cell damage, and the prevention of onion juice to the glutathione depletion reduced by ethanol may be an important factor on the protection from ethanol-induced lipid perpxidation in rats.