Objective To investigate the protective effects of a Yiqi Huatan Quyu formulation on liver injury in chronic intermittent hypoxia rats.Methods Thirty healthy male Sprague-Dawley rats of SPF grade were randomly divided into 3 groups:Group A(normoxia and normal saline gavage),Group B(chronic intermittent hypoxia and normal saline gavage)and Group C(chronic intermittent hypoxia and Yiqi Huatan Quyu formulation gavage)(n =10 in each group).After 8 weeks of treatment,the liver tissue was extracted for protein and RNA.Western blot was used to test the protein levels of B-cellymphoma-2 associated X protein (BAX) and B-cellymphoma-2 (BCL-2),and Realtime PCR was used to test gene expression of BAX and BCL-2.Transferase-mediated dUTP nick end-labeling(TUNEL)was used to assay the apoptotic rate of liver cells.Results The expression of the BAX protein and BAX gene was higher and the expression of the BCL-2 protein and BCL-2 gene was lower in Group B than in Group A(t =13.490 and 16.480,P =0.005 and 0.002;t =5.142 and 9.776,P =0.036 and 0.001,respectively).The levels of the BAX protein and BAX gene were lower and the levels of the BCL-2 protein and BCL-2 gene were higher in Group C than in Group B(t =6.088 and 15.240,P =0.026 and 0.005;t =5.296 and 16.380,P =0.034 and 0.004,respectively).The apoptosis rate of hepatocytes was higher in Group B than in Group A(t =7.698,P =0.002),and was lower in Group C than in Group B(t=4.345,P =0.012).Conclusions The Yiqi Huatan Quyu formulation may alleviate the apoptosis of liver cells in chronic intermittent hypoxia rats by upregulating BCL-2 and down-regulating BAX levels,thus exerting protective effects on the liver.