ObjectiveTo explore the mechanism of Yinchenhao Tang regulating the tumor necrosis factor receptor superfamily member 6 （Fas）/cysteine protease-8 （Caspase-8）/cysteine protease-3 （Caspase-3） signaling pathway to inhibit hepatocyte apoptosis and improve cholestatic liver injury （CLI）. MethodsAmong 48 Wistar rats，12 rats were randomly selected as the blank group，and the other rats were administered alpha-naphthalene isothiocyanate （ANIT） by gavage to induce a CLI model. The modeling rats were randomly divided into the model group， the ursodeoxycholic acid group（0.1 g·kg^-1） and the Yinchenhao Tang group（9.23 g·kg^-1），with 12 rats in each group. The rats in each group were given corresponding drugs by gavage for three consecutive days. The levels of alanine aminotransferase （ALT），aspartate aminotransferase （AST），alkaline phosphatase （ALP），gamma-glutamyl transpeptidase （γ-GT），total bilirubin （TBil） and total bile acid （TBA） in serum were detected. The levels of tumor necrosis factor-α （TNF-α） and interleukin-1β （IL-1β） in liver tissue were detected. The histopathological changes of the liver were observed by hematoxylin-eosin （HE） staining. The protein and mRNA expressions of Fas，Caspase-8，Caspase-3，B-cell lymphoma-2 （Bcl-2） associated X protein （Bax） and Bcl-2 in liver tissue were detected by Western blot and real-time fluorescence quantitative polymerase chain reaction （Real-time PCR）. ResultsCompared with those in the blank group，the levels of ALT，AST，ALP，γ-GT，TBA and TBil in serum of the model group were significantly increased （P<0.01）. The levels and mRNA expressions of TNF-α and IL-1β in liver tissue were significantly increased （P<0.01）. The arrangement of hepatocytes was disordered，and inflammatory cell infiltration and bile duct epithelial cell proliferation were observed. The protein and mRNA expressions of Fas，Caspase-8，Caspase-3 and Bax in liver tissue were significantly increased（P<0.05，P<0.01），while the protein and mRNA expressions of Bcl-2 were significantly decreased （P<0.05，P<0.01）. Compared with those in the model group，the levels of ALP，γ-GT，TBA and TBil in the serum of rats in the ursodeoxycholic acid group were significantly decreased. The levels and mRNA expressions of TNF-α and IL-1β in liver tissue were significantly decreased（P<0.05，P<0.01）. The protein and mRNA expressions of Fas，Caspase-8，Caspase-3 and Bax in liver tissue were significantly decreased （P<0.05，P<0.01），while the mRNA expression of Bcl-2 was significantly increased （P<0.05，）. The levels of ALT，AST，γ-GT，TBA and TBil in the serum of rats in the Yinchenhao Tang group were significantly decreased （P<0.01）. The levels and mRNA expressions of TNF-α and IL-1β in liver tissue were significantly decreased （P<0.05，P<0.01）. The protein expression of Fas and Bax and the mRNA expression of Fas，Caspase-8，Caspase-3 and Bax in liver tissue were significantly decreased （P<0.05，P<0.01），while the protein and mRNA expression of Bcl-2 were significantly increased （P<0.05，P<0.01）. Hepatocyte injury，inflammatory cell infiltration and proliferation of bile duct epithelial cells were reduced. ConclusionYinchenhao Tang can ameliorate CLI，and its mechanism may be related to inhibiting hepatocyte apoptosis mediated by the Fas/Caspase-8/Caspase-3 signaling pathway.