If the stool is black, it is recommended to exclude the interference of food and medication, mainly green vegetables and blood clots. The main drugs are bismuth, iron and some proprietary Chinese medicines. If the food and drug interference factors are excluded, a fecal occult blood test can be done. If the fecal occult blood is positive, the presence of gastrointestinal bleeding is considered. It is recommended to improve the gastroscopy to further identify the cause of gastrointestinal bleeding, and if necessary, to add the examination of Helicobacter pylori. The acid-suppressing drugs can be chosen from omeprazole, pantoprazole, rabeprazole and so on, and the mucosal-protecting drugs are aluminum thioglycollate, aluminum-magnesium plus suspension and so on.