BACKGROUND: Epidural narcotics are now widely used for postoperative pain relief, but their side effects are problematic. Thus, this study was undertaken to evaluate the analgesic effects and to minimize the side effects of the combination of epidural morphine and ketamine versus epidural morphine alone in pateints with postoperative pain. METHODS: The value of using a combined infusion of morphine with a variable dose of ketamine for postoperative analgesia following subtotal gastrectomy was assessed in a double-blind randomised study of 30 patients. Three groups of 10 patients received an infusion of morphine at 2 mg/day, either alone, or combined with ketamine at a rate of 0.4 or 0.6 mg/kg/day. RESULTS: Postoperative anlagesia, sedation, and side effects were not statistically significantly different between groups I and II. Postoperative sedation, and side effects were not statistically significantly different between groups I and III. VAS of group III at 1-2 h was lower than in group I. CONCLUSION: The addition of ketamine to a continuous infusion of morphine dose not significantly improve postoperative analgesia. In addition, increasing the dose of ketamine does not significantly improve postoperative analgesia, Nor does it increase sedation, or side effects.