Blood in the stool after gastroscopy is considered to be the result of biopsy, gastroscopy operation injury, digestive tract diseases, etc. 1. Taking biopsy: under normal circumstances, gastroscopy generally does not lead to blood in the stool, if there is a small polyp in the process of gastroscopy, it is necessary to take out a small polyp tissue samples for biopsy, which will cause a certain amount of damage to the mucous membrane, and there will be varying degrees of bleeding, which may appear in the stool blood, but this situation rarely occurs. 2. Gastroscopy operation damage: gastroscopy is an invasive examination, in some cases, severe cases may be due to the stimulation of the local mucosa with severe nausea and vomiting, which will affect the operation of the doctor’s observation, and in severe cases, may lead to the interruption of the examination, if the patient’s cooperation is poor, it will cause pancreatic mucous membrane tear or pharyngeal injury, laryngeal edema and so on, and pancreatic mucous membrane damage caused by bleeding, and the amount of blood caused by the blood in the stool. 3. Gastrointestinal diseases: patients with existing gastrointestinal diseases may also have blood in stool, such as hemorrhoids, peptic ulcer, intestinal tumors, gastric fundus esophageal varices and so on. Gastroscopy after blood, to communicate with the doctor in time to clarify the cause of symptomatic treatment, after gastroscopy should eat a light and mild.