The analgesic efficacy and duration of action of naproxen sodium 440 mg (n = 92), acetaminophen 1000 mg (n = 89), and placebo (n = 45) were compared in a single-dose, randomized, double-blind, 12-hour study of patients with at least moderate pain secondary to extraction of three or four third molars. Time to remedication, a measure of duration of analgesic effect, was significantly longer (P < 0.001) with naproxen sodium (median, 9.9 hours) than with either acetaminophen (median, 3.1 hours) or placebo (median, 2.0 hours). Naproxen sodium was also superior to acetaminophen for peak pain intensity difference (visual analog scale), summed pain intensity differences, total pain relief, peak pain relief, time to reduction of pain by 50%, and overall rating. The overall percentages of patients reporting adverse events, and the types of events reported, were comparable with the three treatments. Thus naproxen sodium demonstrated superior efficacy and similar tolerability to acetaminophen in this postoperative dental pain model.