Gastroscopy generally has no side effects, but it may also lead to throat damage, esophageal and gastric mucosal damage, bleeding and other hazards. 1. No side effects: Gastroscopy is an examination in which the gastroscope enters through the mouth, passes through the esophagus, cardia and stomach to reach the duodenum and observes whether there is any lesion in the area it passes through. Generally, there are no side effects. 2. Throat injury: when the gastroscope passes through the throat, it may also lead to throat abrasion with symptoms such as throat congestion, edema and ulceration. 3. Gastric and esophageal mucosal injury: gastroscopy, if found in the esophagus or mucosal lesions may need to carry out a pathological biopsy, sampling may lead to mucosal injury. 4. Bleeding: If mucosal damage is caused during gastroscopy, it may lead to bleeding and symptoms such as black stools and vomiting blood. Gastroscopy is a very common examination program, but we can not completely exclude the possibility of side effects, so it is recommended to go to a regular hospital for examination.