The aim of this study is to determine the effect of granisetrone in prevention of post spinal anesthesia shivering. In a randomized clinical trial 105 patients with age 18-60 yr and American society of anesthesia (ASA) class 1-2 who have undergo in lower abdominal surgery randomly allocate in three groups. Group A receive 1 mg intravenous granisetrone, group B 3 mg intravenous granisetrone and group C five ml normal saline intravenously. Before induction of spinal anesthesia, the prepared solutions will be administered intravenously. Same spinal anesthesia at L2-L3 or L3-L4 level will be used in all patients. Bupivacain 0.5% with dose 10-14 mg will be used. No sedative or narcotic will be use after spinal anesthesia. During surgery and recovery, patients will be monitored for shivering, pain, hemodynamic alteration and other complications. During surgery and at post operative care unit, patients will be covered. Oxygen will be administered by face mask for all patients and they will be monitored. Anesthesiologist who is not aware about patients groups, will record the shivering, nausea, vomiting and pain. In addition, any other complications such as hemodynamic alteration will be record. In addition to oxygen therapy, patients with shivering will be warmed.In patients who have shivering with grade 3 or more , petidine (25 mg IV) every 20 minute in maximum three doses will be used