To investigate the proliferation inhibition and apoptosis inducing on human colorectal cancer resistance cell HCT-8/VCR by serum containing Zhi Zhen formula.Methods:MTT assay was used to investigate inhibition on cells, flow cytometry to study cell apoptosis, spectrophotometric method to observe Caspase-3 activity.Results:Different volume fractions of drug-serum could inhibit proliferation of HCT-8 and HCT-8/VCR (P<0.01) , having no statistical differences between the two cell lines. Caspase-3 activity was time-dependent based on observation at 24、48、72、96h time points after 10% ( volume fraction) of the serum was given, reaching peak OD value (1.4) after 72 hours when adapoptosis rate of HCT-8/VCR were higher than that of control group (P<0.01). Conclusion:Serum containing Zhi Zhen formula can inhibit the growth of HCT-8 cells and multidrug resistant HCT-8/VCR by inducing apoptosis, which is dose-dependent and time-dependent under certain conditions and may be related to the increase of Caspase-3 activity.