Abstract: Objective: To investigate the effects of lornoxicam for preemptive analgesia in patients undergoing radical mastectomy and to determine optimal dosage. Methods:Ninety adult patients (ASA I~II), scheduled for radical mastectomy surgery, were randomly divided into 3 groups ( n=30, each group). Group A consisted of patients who received intravenous infusions of 8mg lornoxicam 30minutes before surgery, Group B consisted of patients who received intravenous infusions of 16mg lornoxicam before surgery, and Group C consisted of patients who were administered10ml9% normal saline in-travenously 30minutes before surgery. Postoperative analgesia efficacy was assessed by a numerical rating scale (NRS) at 2, 4, 8, and 24hours after surgery, adverse effects (such as nausea, vomiting, dizziness, hypersomnia, pruritus and uros -chesis, etc.) and requests for analgesia were recorded. Results: The NRS was significantly lower in group A and B than in group C (P<0.05) at 2, 4, 8, and 24hours after surgery, and it was significantly lower in group B than in group A (P<0.05) at 2, 4, and 8 hours after surgery. The total number of cases that requested analgesia during 24hours in group A and B was fewer than in group C ( P<0.05). There was no significant difference in adverse effects after surgery among the 3 groups. Conclusion:Preemptive analgesia with lornoxicam exhibits good analgesic effect in patients undergoing radical mastectomy and reduces the dosage of analgesia and adverse effects. Administration of 16mg lornoxicam for preemptive analgesia can achieve satisfactory efficacy for postoperative analgesia.