Single oral doses of etodolac 50, 100 and 200 mg were compared with aspirin 650 mg and placebo in a double-blind, parallel group study of 189 outpatients reporting moderate or severe pain after oral surgery. Overall efficacy of test drugs was evaluated by sum of pain intensity difference (SPID) scores and total pain relief (TOTPAR) scores over 0.5-3, 0.5-6, 0.5-8 and 0.5-12 hours. Etodolac 200 mg provided significantly greater analgesia than aspirin by these measurements over all SPID and all but one TOTPAR interval, and was significantly more effective than placebo over all intervals. Etodolac 100 mg was superior to aspirin for SPID 0.5-8 and 0.5-12 hours, and superior to placebo for both SPID and TOTPAR over all time intervals. Onset of analgesia for etodolac 100 mg, 200 mg and aspirin was 1 hour or less for the majority of patients in each group; 42% receiving etodolac 200 mg reported onset of analgesia within 0.5 hour. Duration of analgesia for etodolac 200 mg appeared twice that of aspirin. A significant positive dose-response relationship was obtained for the three doses of etodolac. A low frequency of side effects was observed in all treatment groups.