Objective To study the appropriate antibiotic for prophylactic use in cesarean section. Methods The effects and side effects of prophylatic antibiotics in 1 266 cesarean section were studied retrospectively. Six regiems were engaged: (1) Penicillin and Ampicillin; (2) Mezlocillin sodium; (3) Sulbactam and Ampicillin; (4) Ciprofloxacin; (5) Clindamycin; (6) Cefacidal. Results The duration of postoperative body temperature return to normal of 1-6 group is (54.0?28.4) hours, (48.9?27.8) hours, (49.9?23.9) hours, (58.6?33.7) hours, (52.5?25.2) hours, (63.1?51.1) hours respectively. It was longer in cefazolin group than the others. There were less puerperal morbidity and side effects of Mezlocillin. Conclusions Penicillin and Ampicillin are still the most common choices as prophylatic antibiotic in cesarean section. Mezlocillin is appropriate as well.