The analgesic efficacy of a single 200-mg dose of fendosal, a nonnarcotic, nonsteroidal antiinflammatory analgesic, was compared, in a double-blind study, with aspirin 650 mg, ibuprofen 400 mg and placebo in outpatients who had moderate or severe pain after the surgical removal of impacted third molars. Using a self-rating record, patients rated their pain and its relief hourly for up to 12 hours after medicating. Each active medication was significantly superior to placebo. The peak analgesic effect of fendosal 200 mg was similar to that of the aspirin 650-mg standard. Although fendosal's onset of action was slow (3 hours), its effect persisted for 8 hours, substantially longer than that of aspirin. Ibuprofen 400 mg was statistically significantly superior to aspirin 650 mg and fendosal 200 mg for most measures of peak and total analgesia, and its effect persisted for 8 hours. The results of this study raise some questions concerning the comparability of data from studies that employ different criteria for remedication and/or different criteria for the inclusion of data in the analyses of efficacy.