People are not unfamiliar with gastroscopy, but not many people know about painless gastroscopy because some people will feel nausea, dry vomiting and other uncomfortable symptoms when doing ordinary gastroscopy, and many people will have fear of gastroscopy, so doctors have designed painless gastroscopy. Painless gastroscopy means that before the gastroscopy, the doctor injects anesthetic into the patient intravenously, and the patient quickly goes to sleep, so the cricopharyngeal muscles in the mouth will relax, which is more conducive to the insertion of the gastric tube. The main tube, about one centimeter in diameter, is passed from the mouth through the esophagus and stomach cavity to the duodenum, thus illuminating the esophagus, stomach cavity and duodenum. At the front of the gastric tube is a miniature camera, which can keenly record the image of the lumen. The sharp, clear images of the lumen are dynamically presented on the high-definition video display screen. There is no patient discomfort during the examination, and the image acquisition process is stable, which also saves examination time and improves the efficiency of observation. Patients should not smoke the day before the examination, and should not eat for 8 hours and drink for 6 hours before the examination day, and need to be accompanied by relatives. Patients with dentures need to remove them before surgery and inform the doctor of their past medical history before the examination. For patients with underlying diseases, the tolerance of anesthesia should be evaluated by a doctor with relevant expertise. Painless gastroscopy should not be performed during fever and cough.