Epidural morphine infusion is an effective and relatively safe route for postoperative analgesia. Lanz , Theiss , Reiss , and Sommer performed research supporting the use of epidural morphine. Following lumbar epidural anesthesia for orthopedic operations, 174 patients underwent the following study. At the end of surgery under double-blind conditions, 57 patients in group 1 received 0.1 mg/kg of morphine in 15 ml of normal saline epidurally and normal saline 0.01 ml/kg intramuscularly. Patients in group 2 (57 patients) received intramuscular morphine 0.1 mg/kg and normal saline 15 ml epidurally. Patients in group 3 (60 patients) received normal saline 15 ml epidurally and normal saline 0.01 ml/kg intramuscularly. Postoperative pain was less frequent, of shorter duration, and less severe following epidural morphine (group 1). Sympathetic block was only partial; patients still noticed pressure due to a dressing or cast. There was no motor blockade and active mobilization occurred earlier. Following epidural morphine, alertness was heightened, patients were more cooperative, and respiratory depression and postoperative pneumonia were less than after systemic administration of narcotics.(ABSTRACT TRUNCATED AT 250 WORDS)