The purpose of this study was to investigate the effects of glucuronic acid on antioxidative defense system and recovery of muscle fatigue in rat artier aerobic exercise. Sprague-Dawley male rats weighing 150 $pm$ 10g were randomly assigned to one normal(N) group and three exercise training groups. Exercise training groups were classified into glucuronic acid free intubation group(T group), 250mg glucuronic acid/kg bw intubation group(TU group), and 500 mg glucuronic acid/kg bw intubation group(2TU group) according to glucuronic acid supplementation level. The glucuronic acids were administered to rats by oral intubation before exercise training. The experimental rats in exercise training groups(T, TU and 2TU) were exercised on glucuronic acid supplementation or rats in normal group were confined in cage for 4 weeks. And rats were sacrificed with an overdose of pentobarbital injection just after running. Liver xanthine oxidase(XOD) activities were not significantly different among four groups. The activity of superoxide dismutase(SOD) in T group was no significant difference from N group, but those of TU and 2TU groups were increased by 9% and 18%, respectively, compared with that of T group. Liver glutathione peroxidase(GSHpx) activites of T and TU groups showed a similar tendency to that of normal group, but increase 17% in 2TU group compared with normal group. The ratio of GSH/GSSG in liver of T group was lower than that of normal group, but those of TU and 2TU groups were a similar tendency to that of normal group. Contents of thiobarbituric acid reactive substance(TBARS) in T group was increased by 47%, compared with that of normal group but those of TU group and 2TU group were lower 27% and 35%, respectively, compared with that of T group. The contents of glycogen in soleus muscle significantly lower in all three trained exercise groups than that of normal group, but there were no significant differences among the trained exercise groups. Contents of hepatic glycogen in T group were decreased 27% compared with those of normal group while those of TU and 2TU groups were the same as normal group levels. The contents of serum lactic acid in T group were increased 240% of normal group, but hose of TU and 2TU groups were decreased 38%, 39%, respectively, by glucuronic acid supplementations, compared with that of T group. In conclusion, the effects of glucuronic acids in exercise training rats would appear to reduce peroxidation of tissue as an antioxidative defense mechanism and promote recovery of muscle fatigue.