Gastroscopy is recommended in the following cases: when we have upper gastrointestinal symptoms, such as epigastric discomfort, abdominal pain, bloating, acid reflux, heartburn, dysphagia, choking, hiccups, as well as unexplained loss of appetite, weight loss, anemia and so on, gastroscopy is necessary to rule out the presence of upper gastrointestinal tract diseases. Moreover, if there is acute or chronic upper gastrointestinal bleeding of unknown cause, such as vomiting blood, black stool, positive fecal occult blood, etc., it is necessary to go to the hospital for gastroscopy to clarify the cause of the disease on the one hand; on the other hand, if the bleeding patients in emergency, it can also be timely endoscopic hemostasis treatment, and it is also very important to check for the high-risk groups, such as those with a family history of stomach and esophageal cancers or those who live in areas with high risk of stomach and esophageal cancers. It is also very important to examine the population. Gastroscopy is also very effective in following up diseases that require follow-up, such as peptic ulcer, atrophic gastritis with obvious intestinalization, pre-cancerous lesions, and regular follow-up after a major gastrectomy to prevent cancerous lesions from appearing. Endoscopy can also be used for many treatments, such as the removal of foreign bodies for endoscopic treatment, such as gastric polyps, mesenchymal tumors, submucosal masses in the stomach, and smooth muscle tumors in the esophagus or esophageal stenosis, which can be treated endoscopically, and the above mentioned are the common conditions that are often used for gastroscopy.