Objective: To investigate the effects of oxymatrin (OM) and glycyrrhizin (GL) on hepatocyte apoptosis induced by cessation of phenobarbital(PB) treatment in mice. Methods: The Kunming mice were treated with OM (150mg/kg,ip) and GL (50mg/kg,ip) 3times daily during 36h after cessation of PB treatment. Hepatic DNA content and the ratio of liver/body mass of mice were observed to estimate the regressive rate of hyperplastic liver at 36h after withdrawing PB. Histomorphology and the end-labeling method termed TUNEL (TdT-mediated X-dUTP nick end labeling) were used to identify apoptotic cells and DNA in apoptotic cells. Results: Regression ratio of hepatic DNA content and liver/body mass in the positive control group was 32.4%and 16.3%, and 28.9%and 16.1%in the group treated with GL. Hepatic DNA content and liver/body mass in the group treated with OM produced little regression as compared with the negative control group. The results showed that OM markedly inhibited the regression of hepatic DNA content and liver/body mass, but GL showed no effect. Additionally, those mice in the positive control group and the group treated with GL produced a typical hepatocyte apoptotic change with a positive result of TUNEL assay. No hepatocyte apoptotic changes were found in the liver of mice treated with OM, and a negative result of TUNEL assay was presented. Conclusion: OM inhibits the regression of hepatic DNA content and liver/body mass by preventing hepatocyte apoptosis induced by cessation of PB treatment in mice.