Abstract： Objective To investigate the effects of parecoxib sodium on preemptive analgesia and the stress response in elderly patients undergoing laparoscopic cholecystectomy.Methods Totally 40 patients undergoing elective laparoscopic cholecystectomy were randomly divided into two groups:the study group received intravenous parecoxib sodium 40 mg 30 minutes before anesthesia induction,and the control group received normal saline 2 ml instead of parecoxib.Venous blood samples were obtained at 30 minutes before anesthesia induction (T0),at the end of surgery (T1),and 2 hours (T2),24 hours (T3) after the surgery was finished,to determine the plasma levels of serum cortisol and substance P by radioimmunoassay.Visual analogue scale (VAS) scores were recorded at T1,T2and T3.Results In the two groups,plasma levels of serum cortisol at T1,T2 and T3 were significantly higher than those at T0 [study group was (444 ± 123),(532 ± 128),(796 ± 186) nmol/L vs (342 ± 136) nmol/L; control group was(821 ± 187),(913 ± 194),(1036 ±249) nmol/L vs (356 ± 152) nmol/L,respectively] (P ＜ 0.05).In the study group,plasma levels of serum cortisol at T1,T2 and T3 were significantly lower than those in the control group (P ＜0.05).In the control group the plasma levels of substance P at T1,T2 and T3 [(139 ± 10),(147 ± 11),(139 ± 11) ng/L] were significantly higher than those at T0 [(91 ± 9) ng/L] (P ＜ 0.05).But in the study group the plasma levels of substance P at T1,T2 and T3 [(103 ± 9),(111 ± 11),(118 ± 11) ng/L] were not statistically different compared to those at T0[(90 ± 8) ng/L] (P ＞0.05).In the study group VAS scores at T1,T2 and T3 were significandy lower than those in the control group at each time point (P ＜ 0.05).Conclusions Parecoxib sodium can be safely used in elderly patients undergoing laparoscopic cholecystectomy.It can inhibit the stress response effectively and produce preemptive analgesia effect.