Ketorolac is a nonsteroidal anti-inflammatory drug, available in both oral and parenteral forms, that possesses significant analgesic potency. Its analgesic efficacy has been studied extensively for the treatment of moderate-to-severe pain in many clinical settings. Although ketorolac possesses significant analgesic potency, it has limited utility as an analgesic for the acute treatment of moderate-to-severe pain in the emergency department. Oral ketorolac has been shown to provide analgesia that is the same or better than aspirin, acetaminophen, and dextropropoxyphene with acetaminophen, and equal analgesia to most other commonly available oral analgesics, including ibuprofen and acetaminophen with codeine. Intramuscular ketorolac provides analgesia equivalent to commonly used doses of meperidine and morphine. However, its utility in acute pain, when rapid relief is necessary, is limited due to a prolonged onset to analgesic action (30-60 min) and a significant number of patients who exhibit little or no response, more than 25% in most studies. The use of intravenous ketorolac has been less well studied. It has analgesic potency but its utility in patients with moderate-to-severe pain is also limited because there is a significant percentage of patients who fail to obtain adequate relief. Ketorolac may be most useful in supplementing parenteral opiates.