We assessed the antipyretic effectiveness of intravenously administered ketorolac tromethamine in the febrile adult. A double-blind placebo controlled trial enrolling a convenience sample of febrile (T > 38.0 degrees C, oral) patients (18-65 years old) randomized to receive either 0.5 mg/kg (max 30 mg) intravenous ketorolac or placebo. Oral temperatures were recorded every 15 min during the 1-h study period. There were 20 patients in each group. At 60 min, the temperature decrease was 0.4 degrees C (95% CI: 0.0 degrees, 0.7 degrees ) for the control group and 0.8 degrees C (95% CI: 0.5 degrees, 1.1 degrees ) for the ketorolac group. Logistic regression modeling of afebrile at 60 min, controlling for baseline temperature, yielded an odds ratio for ketorolac of 7.1 (95% CI: 1.3, 39.5). In conclusion, our data support that intravenously administered ketorolac has antipyretic properties.