BACKGROUND Ursolic acid is a pentacyclic triterpenoid which has hepatoprotective and antihepatotoxic activities. OBJECTIVE This study investigated whether ursolic acid is able to stimulate liver regeneration in partially hepatectomized mice. METHODS Ursolic acid or the vehicle solution was orally administered to the experimental, sham-operated and vehicle-treated group mice for 7 days, positive control animal (mice) was treated with recombinant human hepatocyte growth factor (rhHGF), and then the 70% liver partial hepatectomy was performed. The liver mass recovery rate was estimated by measuring the ratios of mice liver weight to body weight. The liver cells undergoing DNA synthesis were identified by immunohistochemistry analysis using monoclonal anti-BrdU antibodies. The expression levels of cyclin D1, cyclin E and C/EBP proteins (C/EBPα and C/EBPβ) were detected by the Western blotting technique. RESULTS Our results showed administration of ursolic acid significantly increased the ratio of the liver to body weight and BrdU labeling index at 36 and 48 h after partial hepatectomy, and the potency of UA is similar to rhHGF treated positive control mice. In addition, ursolic acid treatment significantly increased cyclin D1, cyclin E and C/EBPβ protein expression levels at 36 h after liver PHx compared with the vehicle-treated control mice. CONCLUSIONS All these results suggest that ursolic acid stimulates liver proliferation after partial hepatectomy, and this effect may be associated with the stimulation of C/EBPβ expression.