unassigned: Prevention and control of postoperative pains are essential, which affects the prognosis and life quality of patients. Fentanyl is a widely used opioid drug for pre-, intra- and postoperative analgesia. Identifying a patient's genotype before surgery may help to control the fentanyl dose in the perioperative period. unassigned: This study enrolling 645 esophageal cancer (EC) patients was aimed to investigate the associations of gene rs1718125 polymorphism with fentanyl intake and postoperative pains in a Chinese Han population. Genotyping was accomplished by direct sequencing and polymerase chain reaction. unassigned: The GA/AA genotype carriers showed lower visual analog scale scores at postoperative 0, 6 and 24 h, but not at 48 h, compared with the GG genotype. The fentanyl consumption of GG genotype was remarkably more relative to the GA/AA genotype at 6 and 24 h after treatment. unassigned: rs1718125 polymorphism is connected to the postoperative pains and fentanyl use for EC patients.