Cortex Eucommiae is well known in traditional Chinese herbal medicine. The present study investigated the effects of polysaccharides from Cortex Eucommiae (PCE) on exhaustive exercise- induced oxidative stress in mice by measuring the changes in the activities of superoxide dismutase (SOD), glutathione peroxidase (GPX) and catalase (CAT) and levels of malondialdehyde (MDA) and 8-hydroxydeoxyguanosine (8-OHdG). The mice were randomly divided into four groups: a negative control group, a low-dose PCE intervention group, a medium-dose PCE intervention group and a high-dose PCE intervention group. The mice in the control group were given distilled water whereas those in the three intervention groups were given different doses of PCE (10, 50 and 100 mg/kg). After 28 days, the mice were made to perform an exhaustive swimming exercise. Changes in the activities of the main antioxidant enzymes and the levels of MDA and 8-OHdG in the blood, liver and muscle of the mice were measured. The results of the study showed that PCE increased the activities of SOD, GPX and CAT and decreased the levels of MDA and 8-OHdG in mice, suggesting that PCE has a protective effect on exhaustive exercise- induced oxidative stress.