OBJECTIVE The antioxidative system in human hepatocellular carcinoma was investigated.METHODS The activities of cytosolic catalase (CAT), superoxide dismutase, glutathione peroxidase (GSH-Px), glutathione S-tranferase and levels of reduced glutathione, total protein thiols and malondialdehyde were assayed in 10 cases of hepatocellular carcinoma and adjacent normal liver.RESULTS Hepatoma tissues showed higher activities of CAT, GSH-Px and lower content of total antioxidative capacity compared to adjacent normal liver tissue (P＜0.05).CONCLUSION These findings suggest that the antioxidative defenserelated enzymes and antioxidants are largely regulated in hepatoma cells.However, the mechanism which is not clear requires further investigation.