Before painless gastroscopy, cardiopulmonary function tests such as electrocardiogram, chest X-ray, blood routine, coagulation function and other tests are required. Painless gastroscopy is less painful than normal gastroscopy, but it requires general anesthesia, and anesthetics such as propofol may affect cardiopulmonary function, such as lowering of blood pressure, etc. Therefore, there is a certain degree of risk, and cardiopulmonary function needs to be assessed before the examination. For people of advanced age or with underlying diseases, ECG and chest X-rays are usually checked except for absolute contraindications. Other common tests include blood count, coagulation function, and preoperative tests for infectious diseases to prepare for gastroscopy and even microscopic treatment. Painless gastroscopy also requires 8 hours of fasting and other conditions. It is recommended that those who need to undergo painless gastroscopy consult a specialist and prepare for the procedure according to the requirements of the local hospital.