If there are symptoms such as acid reflux, belching and stomach pain, most people’s first choice is to go to the hospital for a gastroscopy. Generally, gastroscopy can see small lesions in the stomach, esophagus and duodenum. However, gastroscopy can easily cause pain, nausea, dryness and vomiting, so doctors have designed painless gastroscopy. The process of painless gastroscopy is actually similar to that of ordinary gastroscopy, except that before the examination, the doctor will inject anesthetic drugs through an intravenous injection so that the patient will soon fall asleep during the examination and the body will not be in a tense state, and after the cricopharyngeal muscles of the mouth become relaxed, it will be conducive to the extension of the gastric tube, which will be passed through a fiber tube of about one centimeter in diameter from the mouth to the duodenum through the esophagus and stomach cavity. The tube is delivered from the oral cavity through the esophagus, the stomach cavity, and the descending duodenum to illuminate the esophagus, the stomach cavity, and the duodenum. The front end of the tube has a miniature camera that records images of the lumen, so that a clear dynamic image of the lumen can be seen on the monitor and small internal lesions, such as gastrointestinal polyps, can be detected early. Painless gastroscopy is a better way to reduce the examination time and discomfort during the examination.