Gastroscopy is generally able to rule out the vast majority of gastric, esophageal and duodenal bulb diseases, but it does not necessarily mean that there is no problem at all and does not exclude the possibility of abnormalities. Generally, a comprehensive examination is needed to determine whether there is no problem, such as urea breath test, tumor marker test, etc. Gastroscopy is a medical examination method, in which a thin, flexible tube is inserted into the stomach and the esophagus, stomach and duodenum are observed through imaging, which can help determine whether there is any local mucosal damage and occupational lesions. If a minor gastric infection occurs during the examination, or if a cancerous lesion in a more obscure area is present, it is not easily detected during the examination and cannot be determined to be OK after gastroscopy. It is necessary to combine other tests, such as carbon 13 urea breath test to determine whether H. pylori infection is present, and also tumor marker screening with the doctor to determine the health of the stomach through a combination of test results. During gastroscopy, the mucous membrane of the stomach may be irritated, so the examination should be performed on an empty stomach to avoid vomiting during the examination and to observe the mucous membrane of the stomach more clearly, which is beneficial to the accuracy of the examination results.