Ciramadol was compared in 30 and 60 mg doses with pentazocine 50 mg, aspirin 650 mg, and placebo in the treatment of 153 patients with postoperative pain. All drugs were administered between six and 72 hours after surgery. Analgesic efficacy was assessed for six hours after study drug administration using verbal pain intensity, analog pain intensity, and verbal pain relief scales. Significantly higher analgesic efficacy scores were seen with ciramadol 30 mg than with pentazocine 50 mg and placebo at most of the evaluation points. Doses of ciramadol 30 mg were significantly more effective than aspirin 650 mg at several time periods, and ciramadol 60 mg was better than pentazocine and placebo at several evaluation times. The 30-mg dose of ciramadol was generally more effective than the 60-mg dose.