A well-controlled comparative study was performed to evaluate efficacy, safety and utility of aspoxicillin (ASPC) as compared with sulbenicillin (SBPC) in the treatment of postoperative wound infections. Either 2 g of ASPC or 2 g of SBPC was administered to patients by intravenous drip infusion twice a day for 7 days. The following results were obtained: Overall clinical effectiveness rates were 82.5% (66/80) in ASPC group and 77.0% (57/74) in SBPC group, with no statistically significant difference between 2 groups. Final overall clinical improvement rates were 83.8% (67/80) in ASPC group and 81.1% (60/74) in SBPC group, with no statistically significant difference between 2 groups. As to bacteriological effectiveness, eradication rates of clinical isolates were 70.4% (38/54) in ASPC group and 74.4% (32/43) in SBPC group. There was no statistically significant difference in 2 groups. Side effects and abnormal laboratory findings were observed in 6 cases (6.7%) and 11 cases (12.4%) in ASPC group (89 cases) respectively, and 4 cases (4.4%) and 7 cases (7.8%) in SBPC group (90 cases) respectively. Especially severe adverse reactions were not observed, and there was no significant difference in the incidences of side effects and abnormal laboratory findings between 2 groups. As to overall clinical utility, utility rates were 77.5% (62/80) in ASPC group and 70.3% (52/74) in SBPC group. There was no statistically significant difference between 2 groups. These results may be indicated that ASPC is as useful as SBPC in the treatment of postoperative wound infections.