We designed a randomized, double-blind study to assess the analgesic efficacy and safety of perioperative ketorolac infusion in 95 patients undergoing cholecystectomy. The ketorolac group (n = 48) received premedication, combined with ketorolac 30 mg intramuscularly (IM), followed by a ketorolac continuous infusion (2 mg/h). The control group (n = 47) received an IM bolus of NaCl 0.9% (1 mL) followed by continuous saline infusion (2 mL/h) for 24 h. Operative blood losses, postoperative pain, sedation, and on-demand morphine consumption (patient-controlled analgesia [PCA]) were measured. The effects on plasma catecholamines, cortisol, potassium, creatinine, skin bleeding time, prothrombin time (PT), and partial thromboplastin time (PTT) were also evaluated. Ketorolac improved pain scores (P < 0.05) and reduced plasma cortisol concentrations between 2 and 6 h (P < 0.05). No significant differences were observed concerning operative blood losses, glucose concentration, and renal and hemostatic functions. The ketorolac group required less morphine (not significant [NS]) than the control group and had less adverse effects (P = 0.002). Thus, perioperative ketorolac infusion improved the quality of postoperative pain relief, and had no major influence on endocrine-metabolic response and no negative influences on hemostatic and renal functions. This study suggests that preventive ketorolac administration, followed by a continuous infusion, is an easy, useful, and safe method for pain control after abdominal surgery.