The aim of this study was to evaluate the effect of hot water extract of peduncle obtained from Hovenia dulcis Thunb (HD) which is commercially developed for the protective effect on the alcoholic hepatotoxicity, on the endurance capacity for weight loaded forced swimming mice. The swimming times to exhaustion in mice fed 100 and 200 mg/kg HD for 2 weeks were prolonged 3.6 and 3.7 fold, and for 4 weeks 1.9 and 2.7 fold compared with each vehicle control ($42.8{pm}20.5$ min and $67.7{pm}47.8$ min, for 2 and 4 weeks), respectively. Blood biochemical parameters for ALT, AST, creatinine and BUN were not significantly different between from HD fed or control mice. Although HD fed mice swam over 2 fold longer time than vehicle control mice at 4 weeks, blood biomarkers of physical fatigue such as glucose, triglyceride and free fatty acid, lactate were not significant different and even tended to ameliorate. Hepatic lipid peroxidation and SOD activity did not significantly change in HD fed- and vehicle control exhausted swimming mice at 2 or 4 weeks. However, catalase activity in HD-fed mice was significantly increased in a dose-dependent manner compared with vehicle control mice. The present study indicates that HD improved physical fatigue and exercise performance in mice. Therefore, it has a potential for the pharmacological effect of anti-fatigue.