DFP [3-(2-propyloxy)-(4-methyl-sulfonylphenyl)-(5,5-dimethyl)-fu ranone] is a highly specific cyclooxygenase-2 inhibitor (>2500-fold selective in transfected Chinese hamster ovary cell assays) that has demonstrated efficacy in preclinical models of pain and inflammation. The present single-dose, randomized, double-masked, double-dummy, placebo-controlled, parallel-group study was undertaken to compare DFP 5, 25, and 50 mg with naproxen sodium 550 mg and with placebo in 196 patients (mean age, 25.8 years; 187 [95.4%] males) who experienced moderate-to-severe pain after surgical removal of > or =2 third molars. Overall analgesic effect, duration of effect, time to onset of analgesic effect, peak analgesic effect, and tolerability were assessed over a 24-hour postdose period. Both DFP 25 and 50 mg, as well as the active comparator, naproxen sodium 550 mg, were significantly more effective than placebo. The onset of analgesic effect in the DFP 25-mg, DFP 50-mg, and naproxen sodium 550-mg groups did not differ significantly. DFP was generally well tolerated in single doses up to 50 mg. DFP 50 mg was efficacious in the treatment of postoperative dental pain and was indistinguishable from the active comparator, naproxen sodium 550 mg.