Objective To study the inhibitory effects of dehydroepiandrosterone (DHEA) and its metabolites-dehydroepiandrosterone sulfate (DHEAs) on the proliferation of HepG2 and HT-29 and their mechanism.Methods HepG2 and HT-29 were incubated by DHEA or DHEAs with different concentrations (1,10,50,100 and 200 ?mol?L-1) for 8,24,48,72 h and routine culture was used as control.The inhibitory rate was detected by using MTT chromometry and BrdU assay respectively.The activities of 3-hydroxy-3-methylglutaryl coenzyme A reductase(HMGR),glucose -6-phosphate dehydrogenase (G6PD) and lactate dehydrogenase (LDH) were examined simultaneously.Results ①MTT chromometry:DHEA with different concentrations obviously inhibited the growth of HepG2 and HT-29 cells compared with control group(P0.05).②BrdU assay:the growth of cells were significantly inhibited by DHEA with concentrations of 50,100 and 200 ?mol?L-1,especially to HepG2 cells(P0.05).Conclusion DHEA has strong anti-proliferative effects on both HepG2 and HT-29 cell lines and inhibitory effects on the activities of G6PD or HMGR,however,DHEAs has no obvious effect.