Common complications include the following: first, postoperative bleeding. If there is intra-abdominal bleeding, the patient will show signs of bacterial shock, which can be life-threatening, and should be closely observed after surgery. The second is wound infection, or infection of the abdominal cavity. The third is anastomotic obstruction, which is manifested as abdominal distension, nausea and vomiting after removing the gastric tube, or after eating, and the vomit can contain gastric contents or bile mixed with bile. Most anastomotic obstruction is caused by anastomotic edema. Most of them can be relieved after symptomatic treatment.