Painless gastroscopy technique is based on ordinary gastroscopy with intravenous injection of drugs such as isoproterenol and fentanyl. Because of the sedative and analgesic effect of intravenous isoproterenol, and their fast onset, fast recovery, short half-life, strong controllability, and no accumulation in the body, patients quickly enter the snoring state during gastroscopy, and the smooth muscle relaxation of the digestive cavity helps gastroscopy advance, and patients cooperate better, which is conducive to careful observation of lesions, especially for some gastroscopic treatments that require good patient cooperation, such as polyp removal, hemostasis, or large mucosal resection, etc. It is especially useful for gastroscopic treatments that require good patient cooperation, such as polyp removal, foreign body removal, hemostasis, or large mucosal resection, etc. The patient has no memory of the gastroscopy after waking up. Caution: 1. Avoid smoking the day before the examination to avoid coughing during the examination. 2, be accompanied by an adult relative or friend, and remove dentures before the procedure. 3, the day before the examination should not eat after dinner, the morning of the examination should not drink water, colonoscopy requires intestinal preparation. 4, inform the doctor of your past medical history and drug allergy history. 5.Someone should accompany you within 3 hours after the examination. 6.No spicy food and no alcohol within 8 hours after the examination. 7.It is best not to drive motor vehicles, operate machinery and engage in overhead work for 2 days after the examination to prevent accidents. It is better to suspend the work that requires actuarial and logical analysis.