The application of painless gastroscopy technology has greatly reduced the pain of patients. In recent years, with the development of sedative anesthetics and advances in endoscopy technology, there are now a variety of sedative anesthetics used to assist gastroscopy. Fentanyl is currently the most commonly used anesthetic analgesic, which not only inhibits somatic pain, but also has an antagonistic effect on visceral pain and discomfort. Isoproterenol, as a rapid, short-acting intravenous anesthetic, has the advantage of being highly controllable, has a significant anti-vomiting reflex and inhibits the contraction of the smooth muscle of the gastrointestinal tract, reduces nausea, vomiting, choking and other discomfort reactions, but has a large effect on respiratory and circulatory depression, which can cause a drop in blood pressure, slowed heart rate, respiratory depression or pause, so pay attention to the control of speed and dose, adequate oxygen administration and close monitoring in the application. In the general gastroscopy group, 100% of patients had nausea and 12.6% of patients experienced vomiting; while in the painless gastroscopy group, very little nausea and vomiting occurred, suggesting that painless gastroscopy is highly comfortable and the examination process is smooth, which is consistent with the reported results. In addition, no pancreatic mucosal tears and mandibular joint dislocations were seen in the painless gastroscopy group, which may also be due to their rare vomiting reactions. The complications such as sore throat and gastric abrasion were significantly reduced in the painless gastroscopy group, but the incidence of duodenal abrasion was higher than that of ordinary gastroscopy, which may be due to the characteristics of the two operations, analyzed as follows: 1. Painless gastroscopy is easy to insert into the esophagus, and the probability of injury to the throat is low. The anatomical areas are easily displayed, and the probability of the front end of the scope rubbing the pharynx due to “blind entry” is reduced. And because vomiting is rare, the resulting gastric contents and acid reflux are reduced, and the chemical erosion of the mucosa of the oropharynx by the refluxed material is reduced. 2, painless gastroscopy is easy to pass through the fundus and pylorus, and the probability of inadvertently bruising the gastric mucosa during the operation is reduced, while the patient is in a shallow sleep state and does not vomit the injected gas, the gastric peristalsis is reduced, and the pylorus swing amplitude is small, which is conducive to the accuracy and reliability of the operator’s series of maneuvers such as passing through the fundus and entering the pylorus. In contrast, the nausea reaction induced by conventional gastroscopy causes retroperistalsis of the duodenum toward the mouth, shortening its total longitudinal pathway and making it easier to reach the descending duodenum by bypassing the superior duodenal bend at the apex of the scope compared to painless gastroscopy, thus reducing the probability of inadvertent duodenal abrasion. The incidence of eructation and choking was significantly lower in the general gastroscopy group, which may be related to the altered sensitivity of the respiratory system to stimulation by sedative anesthetics such as isoproterenol and fentanyl. In addition, data showed that patients with choking in the painless gastroscopy group had a higher history of acute respiratory infections, suggesting that concomitant acute respiratory infections may increase the incidence of choking in painless gastroscopy, and the mechanism is not clear. In conclusion, the common complications of conventional gastroscopy and painless gastroscopy have different incidence rates, and the reasons for this difference may be related to the characteristics of the gastroscopic procedure under anesthesia and sedative anesthetics.