Upper gastrointestinal endoscopy is generally not harmful to the body, but a small number of patients may have complications such as abdominal distension, nausea and vomiting, bleeding and perforation during or after the examination due to low tolerance and poor compliance. 1. Abdominal distension, nausea and vomiting: Upper gastrointestinal endoscopy is generally the endoscope from the mouth or nasal cavity into the esophagus and stomach through the pharynx and throat, the endoscope into the stomach may pull the smooth muscle of the stomach or cause gastric mucosal congestion and edema leading to nausea and vomiting symptoms. During the examination, some gas will be injected into the gastrointestinal tract, and abdominal distension may occur after the examination, which can be relieved after exhaustion. 2. Bleeding: Upper gastrointestinal endoscopy is a kind of invasive examination, in the process of entering the stomach will be friction and collision with the surrounding mucous membrane tissues and thus mechanical damage occurs, gastric mucosal bleeding. Bleeding of the esophageal mucosal tear may also occur. 3. Perforation: Perforation of the gastrointestinal tract, such as pear-shaped crypt or duodenal perforation, may occur due to the operator’s inexperience and the patient’s uncooperative behavior. Perforation may be followed by mediastinal emphysema, pneumothorax, subcutaneous emphysema, retroperitoneal pneumoperitoneum and other manifestations, which should be handled promptly by the surgeon. Overall, complications of upper gastrointestinal tract electronic endoscopy are very unlikely, and patients should actively cooperate with doctors to avoid complications.