Objectives:To determine the efficacy of preemptive hydromorphone for laparoscopic radical gastrectomy.Methods:The present prospective and double-blinded study was performed in the The First Hospital, Jilin University, Changchun, China, between July 2017 and April 2018. Fifty patients scheduled for laparoscopic radical, gastrectomy were equally randomized into 2 groups, which were administrated different drugs 10 minutes before surgery. Group P (the preemptive hydromorphone group) was administrated 2 mg hydromorphone (2 mL), and Group C (the control group) was administrated 2 mL normal saline intravenously. A standardized general anesthesia were conducted. Blood pressure and heart rate, postoperative morphine consumption, pain intensity, sedation status, and side effects were recorded.Results:Group C had larger intraoperative hemodynamic changes, higher postoperative visual analogue scale score, more morphine consumption and lower overall satisfaction degree than Group P. No difference was found between the 2 groups in sedation status and adverse effects.Conclusion:Preoperative 2 mg hydromorphone could reduce intraoperative changes of blood pressure and heart rate, postoperative pain intensity, and morphine consumption without an increase of adverse effects.