This study was undertaken to investigate the inhibition effects of Auricularia auricula-judae methanol extract in edible mushroom on lipid peroxidation and liver damage in benzo(a)pyrene(B(a)P)-treated mice. The activities of serum aminotransferase, cytochrome P-450, superoxide dismutase, catalase, glutathione peroxidase and the hepatic content of lipid peroxide after B(a)P-treatment was markedly increased than control but those levels were significantly decreased by the treatment of Auricularia auricula-judae methanol extract. Glutathione S-transferase activity and the hepatic glutathione content were decreased by B(a)P-treatment than control, but those were also inhibited by the treament of Auricularia auricula-judae methanol extract. These results suggest that Auricularia auricula-judae methanol extract have a protective effect on liver damage by B(a)P.