The aim of this was to evaluate the effects of Rhus Verniciflua Stoke (RVS) extract powder on the endurance capacity for the forced swimming mice. Thirty mice were divided into 3 groups including negative control, 250 (RVS-250) and 500 (RVS-500) mg/kg RVS extract powder groups for 4-times swimming exercises. The swimming times to exhaustion in RVS-250 and RVS-500 mice were prolonged 1.6- and 2.0-fold at 4 weeks compared with negative control mice, respectively. Blood biochemical parameters for AST, ALT, T-CHO and TG were not significantly different between RVS fed or negative control mice. However, blood concentration of creatinine was significantly increased in RVS-250 mice, but not in RVS-500 mice. During the longer swimming exercise in RVS group, blood glucose and lactate levels were significantly decreased, but free fatty acid not changed. And also LDH levels were significantly decreased in RVS groups compared to negative control mice. Hepatic lipid peroxidation was not affected by RVS, but SOD and catalase activity were significantly increased in RVS groups. Interestingly, the levels of testosterone and free testosterone were significantly increased in RVS groups before swimming exercise, but they were not significantly changed among groups after swimming exercise. The present results suggest that RVS extract powders may enhance swimming exercise performance by recovering the exercise-fatigue via reduction of blood LDH activity and by burning blood glucose as an energy source. These results imply that RVS-produced testosterone may act as an energy buster to enhance physical activity.