This study is to evaluate of the effects of diclofenac suppository and intravenous acetaminophen, and the combination of them on postoperative pain in patients undergoing spinal anesthesia for cesarean section. Objectives: To investigate the effect of diclofenac suppository and Intravenous acetaminophen and the combination of them on the severity of postoperative pain in patients undergoing spinal anesthesia for cesarean section in Sayyad Shirazi health education center of Gorgan in 1393. Design: This study is randomized, double-blind. Setting and conduct: 90 patients scheduled for cesarean surgery will be randomly divided into three groups: A. 100 mg diclofenac suppositories, B.1000 mg intravenous acetaminophen, and C.50 mg of diclofenac suppositories and 500 mg intravenous acetaminophen. In the recovery, based on severity of pain measured by visual analogue scale (VAS), if the patients have moderate pain medication will be given. Main inclusion criterion: ASA class of 1 and 2, term gestational age. Main exclusion criteria: any allergies to medications such as acetaminophen and local anesthetics, liver and kidney diseases and diabetes. Interventions: Assessment of pain severity at 0, 2, 4, 6, 12, 24 and administration of nonsteroidal anti-inflammatory drug in three groups according to their average pain severity measured by (VAS). Main outcome measures: determination of pain severity in the groups.