Aim: To investigate the mitochondria-initiated apoptosis pathway involved in Carbon tetrachloride (CCl_4) hepatotoxicity in vitro. Methods: Several cytotoxic-ity endpoints, including WST-8 metabolism, lactate dehydrogenase leakage and morphological changes, were examined. The 5,5’-dithio-bis(2-nitrobenzoic acid) reaction was used to measure reduced glutathione level, and the malondialdehyde level was determined using the thiobarbituric acid assay. The release of cyto-chrome c and Bcl-X_L was detected by Western blot. Caspase-3 activity was mea sured using the fluorogenic substrate Ac-DEVD-AMC. DNA fragmentation wasused to evaluate cell apoptosis. Results: A time-and dose-dependent decrease in cellular glutathione content was observed, along with a concomitant increase in malondialdehyde levels following the application of CCl_4. Caspase 3 activity was stimulated at all doses of CCl_4, with the most significant activation at 3 mmol/L. Cytochrome c was released obviously after CCl_4 treatment. A time-dependent decrease in BcI-X_L expression was observed. DNA fragmentation results revealed apoptosis and necrosis following CCl_4 treatment. Conclusion: Oxidative damage is one of the essential mechanisms of CCl_4 hepatotoxicity, which triggers apoptosis via the mitochondria-initiated pathway. Aim: To investigate the mitochondria-initiated apoptosis pathway involved in Carbon tetrachloride (CCl 4) hepatotoxicity in vitro. Methods: Several cytotoxic-ity endpoints, including WST-8 metabolism, lactate dehydrogenase leakage and morphological changes, were examined. The 5,5 ’ The release of cyto-chrome c and Bcl-X_L was detected by Western blot. Caspase- 3 activity was mea sured using the fluorogenic substrate Ac-DEVD-AMC. DNA fragmentation was used to evaluate cell apoptosis. Results: A time-and dose-dependent decrease in cellular glutathione content was observed, along with a concomitant increase in malondialdehyde levels following the application of CCl_4. Caspase 3 activity was stimulated at all doses of CCl_4 with the most significant activation at 3 mmol / L. Cytochrome c was released obviously after CCl_4 trea A time-dependent decrease in BcI-X_L expression was observed. DNA fragmentation results revealed apoptosis and necrosis following CCl_4 treatment. Conclusion: Oxidative damage is one of the essential mechanisms of CCl_4 hepatotoxicity, which triggers apoptosis via the mitochondria-initiated pathway.