Abstract: To investigate the effects of Radix Puerariae water Extract (RPE) on exercise-induced fatigue, 96 mice were randomly divided into four groups: Normal Control (NC), Low dose RPE Treated (LRT), Middle dose RPE Treated (MRT) and High dose RPE Treated (HRT) groups. The mice in the treated groups received RPE (2, 4 and 8 g kg-1, ig) and the mice in the normal control group received drinking water ig for 4 weeks. The exhaustive swimming time, Blood Lactic Acid (BLA), Blood Urea Nitrogen (BUN), Hemoglobin (Hb) and liver glycogen were determined after swimming test. The results indicated that RPE had significant anti-fatigue effects on mice. It extended the exhaustive swimming time of mice, increased the Hb and liver glycogen contents and decreased BLA and BUN contents.