The intermittent injection of analgesics is a inadquate method for postoperative pain control. Recently a non-electroic, disposable and portable infusor (Boxter Two Day $Infusor^R$) has been developed which can deliver analgesics with 2 ml/h speed continuousely. The present study examined the effects of three methods of pain management on recovery in 306 patients undergoing elective surgery in Wonkwang University Hospital. Group 1 (n=106) received i.m. $Valentac^R$ on a PRN basis. Group 2 (n=100), initial 2 mg of bolus morphine was followed by 48 mg of continuous infusion. Group 3 (n=100), initial 2 mg of morphine followed by morphine 18 mg-ketorolac 120 mg. We evaluated an analgesic efficacy with NRS (numerical rating scale) at 12, 24, 36, 48, 60 and 72 hours after the operation. The side effects (nausea, vomiting, pruritus, sedation and respiratory depression) were evaluated. In group 1, we asked major concern before operation and efficacy of pain control with pain severity (no pain, mild pain, moderate pain, sever pain). The results were as follows: 1) Major concern before operation is pain (40%). 2) 53% of patients suffered pain in group 1. 3) Morphine and morphine-ketorolac infusion groups were superior to the i. m. ($Valentac^R$) group with respect to postoperative analgesia. 4) In group 3 (morphine-ketorolac), there was no pruritus and mild nausea and vomiting.