Ketorolac, a nonsteroidal anti-inflammatory drug, is alleged to produce postoperative analgesia without opioid-related side effects. Patients undergoing laparoscopic cholecystectomy were assigned randomly to receive either ketorolac or a placebo (saline) according to a double-blind protocol. Preoperative (baseline) pulmonary function was evaluated using a Respiradyne II monitor. Patients received midazolam, 2 mg, and 2 mL of either ketorolac, 60 mg (n = 311, or saline (n = 29), 20–40 min before surgery. Anesthesia consisted of thiopental, 4–5 mg/kg, and vecuronium, 0.1 mg/kg, for induction, and isoflurane, 0.5%–2.0%, with 67% nitrous oxide in oxygen for maintenance. A second 2-mL dose of the same study medication (ketorolac, 60 mg, or saline) was administered 4 h after the initial dose. Post-operatively, 66% of patients in the saline group complained of pain requiring treatment with fentanyl compared to 32% in the ketorolac group (P