BACKGROUND: Pain management in the terminal stage of advanced cancer is often complicated by opioid-related bowel syndrome and other problems. This study was conducted to investigate the safety and efficacy of ketorolac as an adjunctive analgesic in cancer pain management. METHODS: 10 acutely ill cancer patients suffering from pain, complications of advanced disease, and opioid side effects were included. Except one acute leukemia, all of the patients had metastatic solid tumors. Pain complaints consisted of visceral, somatic and opioid bowel syndrome. They were treated with intravenous morphine patient-controlled analgesia infused with a repeated ketorolac bolus dosing. Demographic data, cancer diagnosis, change of pre- and post-treatment morphine infusion rates, and days until pain control or relief of opioid bowel syndrome were evaluated. RESULTS: Excellent pain relief with improvement of opioid bowel syndrome was achieved in a majority of cases. Ketorolac showed good morphine sparing effects. None of the patients reported gastrointestinal side effects. CONCLUSION: Ketorolac appeared to be well-tolerated in the clinical dose range and for short-term use in acutely-ill terminal cancer pain patients. It also seems to be very effective in relieving opioid-related bowel syndromes.