In a randomized prospective stratified trial consisting of 1010 patients undergoing abdominal surgery involving the viscera, the efficacy of cefotaxime plus metronidazole was compared to cefoxitin for preventing wound infection. The efficacy of a single dose of antibiotics versus three doses over 24 hours was also evaluated. This study demonstrated that a single-dose antibiotic regimen was as effective as a multiple-dose regimen in the prophylaxis of wound infections following abdominal surgery. In addition it demonstrated that the cefotaxime plus metronidazole regimen is comparable to that of cefoxitin and is more cost-effective. It is concluded that a single dose of cefotaxime plus metronidazole provides effective prophylaxis against postoperative wound infections following abdominal surgery.