In a double-blind, placebo-controlled, single-dose, parallel-group study, oral doses (5, 10 and 25 mg) of the prostaglandin synthetase inhibitor bromfenac were compared with acetaminophen (1000 mg) and placebo for postoperative orthopedic pain. Analgesic measurements were made by nurse observers by use of standard verbal rating and visual analog scales. For most pain intensity and pain relief measurements, 1000 mg acetaminophen was statistically superior to placebo, demonstrating assay sensitivity, and 10 and 25 mg doses of bromfenac were statistically better than both placebo and 5 mg bromfenac for ordinal and analog ratings of pain intensity and pain relief; 25 mg bromfenac produced significantly longer time to remedication than acetaminophen. The 5 mg dose of bromfenac was statistically superior to placebo for some measures, including remedication time. There were no untoward adverse effects or alterations in vital signs. Overall, 10 mg bromfenac produced analgesia equivalent to that of 1000 mg acetaminophen in this pain context.