The purpose of this study was to characterize the analgesic dose-effect curve of orally administered fendosal, relative to aspirin 650 mg and placebo. A total of 153 patients experiencing moderate to severe pain due to extraction of impacted molar teeth completed this two-part, single-dose, double-blind, randomized trial. In part I, the possible treatments were placebo, aspirin 650 mg, fendosal 100 mg and fendosal 200 mg. In part II, fendosal 400 mg replaced the fendosal 100 mg treatment. Fendosal 100 mg was not an analgesic dose but 200 and 400 mg were on the ascending portion of the dose-effect curve. Fendosal 200 mg was superior to placebo and about equal to aspirin in total effect but not peak effect. Fendosal 400 mg was statistically superior to both fendosal 200 mg and placebo. Fendosal 400 mg appears to provide analgesia similar to that of aspirin 650 mg but with a substantially longer duration.