A randomized study was carried out on 123 patients underwent laparoscopic cholecystectomy. The patients were divided into two groups: one group used antibiotic prophylaxis (63 patients) and the other used postoperative antibiotic therapy (60 patients). Antibiotic prophylaxis can be administered by oral route, intramuscular injection or intravenous injection. Oral drugs were used at 6 to 12h before surgery. Intramuscular injections were performed at 1 to 2h before surgery and intravenous injection was most commonly used at beginning of anesthesia. Antibiotic prophylaxis was indicated for clean-infective surgery. The effects of antibiotics in two groups were not different. Cost of antibiotic prophylaxis was 3-5 folds cheaper than postoperative antibiotics