Effective pain management of the endodontic emergency patient is often a problem. Ketorolac tromethamine is the first nonsteroidal anti-inflammatory drug available for intramuscular injection in the United States. Although its analgesic efficacy is comparable with opiates after intramuscular injection, to date no study has evaluated its efficacy after intraoral periapical injection. Fifty-two endodontic emergency patients were injected (injection routes = intraoral infiltration/intramuscular deltoid) on a double-blind basis with either: (i) placebo/placebo, (ii) 30 mg ketorolac/placebo, (iii) placebo/30 mg ketorolac, or (iv) 2% mepivicaine with 1:20 K levonordefrin/placebo. Infiltration injection of ketorolac at on oral site produced significant analgesic effects, particularly in treating pain of mandibular origin. These results suggest that intraoral injection of ketorolac may prove to be a useful adjunct in the management of endodontic pain patients. Further studies are required to replicate these findings and to develop optimal treatment combinations.