Ketorolac tromethamine[(+/-)-5(benzoyl)-2,3-dihydro-1N-pyrrolizine-1-carboxylic acid tris hydroxymethylaminomethane salt] is a highly potent member of a new class of compounds having analgesic and anti-inflammatory activity. When given orally in tests involving underlying inflammation it was a potent analgesic, whereas it was inactive in tests for narcotic activity. It was also highly active orally in rat models of acute and chronic inflammation and pyresis. These properties are mediated primarily via the compound's potent prostaglandin cyclooxygenase inhibitory activity. The agent elicited mild CNS and cardiovascular activity only at doses far in excess of those required for analgesic and anti-inflammatory activity. A single 10 mg tablet given orally to human volunteers following surgery provided pain relief equivalent to that provided by 10 mg of morphine given intramuscularly. When given intramuscularly to rabbits (0.25 ml of a 0.31-5% solution) or man (3 ml of a 1-3% solution), no drug-related irritation or changes in creatine phosphokinase were seen. Solutions (less than or equal to 0.5%) applied to the eyes of animals and man were not irritating. When applied topically in rat and rabbit models of ocular inflammation, less than or equal to 0.5% solutions of ketorolac tromethamine inhibited the inflammatory response.