1.Severe cardiopulmonary disease (arrhythmia, heart failure, heart attack, respiratory insufficiency, asthma attack, high blood pressure). 2.Critical state such as shock, coma, etc. 3.Delirium and mental disorders. 4.Acute perforation period of upper gastrointestinal tract. 5.Severe pharyngeal disease, corrosive esophagitis, gastritis, aortic aneurysm, severe cervicothoracic and spinal deformity. Wang Lirong, Department of Gastroenterology, Nanjing Second Hospital 6, acute infectious hepatitis or gastrointestinal infectious disease withholding examination, and patients whose doctors think they are not suitable for gastroscopy.