In this study we evaluated whether the free radical scavenger (edaravone) could suppress rat lower extremity postoperative reperfusion injury by evaluating dose response and skeletal muscle viability. Fifteen Lewis male rats (450-570 gm) were divided into three groups by the dosage of edaravone (3.0 and 9.0 mg/kg, n = 5 each). Both common femoral arteries were clamped for 5 h and then declamped. At 5 h after reperfusion, serum creatine phosphokinase (CPK) levels were examined. The muscles of lower extremity were harvested, in order to count the numbers of viable rat muscle cells under 400 x magnifications. After 3.0 mg/kg of edaravone was given preoperatively, serum CPK levels were lower (797 ± 173 IU/ml) than the control group (1,438 ± 280 IU/ml). The mean number of rat muscle cells in the 3.0 mg/kg edaravone group was significantly greater (951 ± 168 cells/mm2, p = 0.002) than both the control group (258 ± 31 cells/mm2) and 9.0 mg/kg edaravone group (390 ± 82 cells/mm2). This study suggests that the preoperative administration of "3.0 mg/kg of edaravone" could suppress postoperative reperfusion injury in a rat model. © 2006 Springer Science+Business Media, Inc.