All types of esophageal, gastric, and duodenal diseases can be examined, including inflammation, ulcers, tumors, stones, diverticula, and structural abnormalities such as strictures. Gastroscopic examination of diseases include: 1, esophageal diseases: such as reflux esophagitis, mycosis fungoides, esophageal varices, esophageal ulcers, esophageal polyps, and esophageal cancer can be confirmed by gastroscopy. 2, gastritis: the color of the gastric mucosa and the vascular permeability can be judged as atrophic gastritis or superficial gastritis. 3, gastric ulcer: the mucosa is broken, incomplete, the trauma may involve blood vessels and bleeding, gastric ulcer may also be malignant lesions, such as gastric cancer. 4, gastric tumor through gastroscopy can find out whether there are ulcers in the inner wall of the duodenal tissue. 5, gastric polyps: Gastroscopy can be done to determine the specific nature of polyps from the bulging changes in the lining of the stomach after biopsy. 6, gastric stones: Some foods containing tannin will solidify and form stones under the action of stomach acid. 7.Gastric foreign body: The foreign body swallowed by mistake can be observed under gastroscopy and removed with special instruments. 8, gastric bleeding: Gastroscopy can also be used to determine gastric bleeding through the presence of excessive blood accumulation in the stomach tissue, and find the site of bleeding, lesion characteristics, can also be done under the gastroscope to stop bleeding treatment. 9. Gastroscopy is also able to observe and judge the lesions of the duodenum. Gastroscopy is not suitable for everyone, and gastroscopy can only be determined after an interview with a doctor.