Both treatment and pretreatment of the cultured rat primary hepatocytes with T. chebula aqueous fruit extract (500 or 1000 mg/kg body weight for 5 days) significantly reversed the t-BHP-induced cell cytotoxicity and lactate dehydrogenase leakage. In addition, T. chebula extract exhibited in vitro ferric-reducing antioxidant activity and 2,2-diphenyl-1-picryhydrazyl free radical-scavenging activities. Histopathologic examination of the rat livers showed that T. chebula extract reduced the incidence of liver lesions including hepatocyte swelling and neutrophilic infiltration, and repaired necrosis induced by t-BHP 47. Further, a hepatoprotective compound, isolated from the ethanolic extract of the fruits of T. chebula, was identified as a mixture of chebulic acid and its minor isomer, neochebulic acid that also reduced the tert-butyl hydroperoxide (t-BHP)-induced cell cytotoxicity in isolated rat hepatocyte experiment 48. An aglycone isolated from the fruits of T. chebula, triethylchebulate, significantly inhibited FeSO4 /Cys-induced microsomes lipid peroxidation and protected both H2O2- -induced RBCs hemolysis and RBCs auto-hemolysis in a dose-dependent manner. Furthermore, triethylchebulate demonstrated potent DPPH free-radical scavenging ability and moderately suppressed azide-induced mitochondria ROS formation. The results demonstrated that triethylchebulate was a strong antioxidant and free-radical scavenger, which might contribute to the anti-oxidative ability of T. chebula