Patients with gastrointestinal discomfort and black stools consider three causes, as follows: First, improper eating: eating a lot of greasy, high-protein food, stomach distension, discomfort, and will appear black stools because of slow emptying of the stool. Second, the impact of drugs: the use of drugs, such as bismuth, iron, easy to stimulate the gastrointestinal, causing gastrointestinal discomfort, and will appear black stool color. Third, gastrointestinal bleeding: gastrointestinal discomfort, dark stool color, be alert to the occurrence of gastrointestinal bleeding, adults with daily bleeding > 5mL, positive fecal occult blood test, if the bleeding amount > 50mL, it can appear black stool or tarry stool. Therefore, when the stool is dark, be highly alert to gastrointestinal bleeding, and promptly go to the hospital to check the fecal occult blood test and blood count, etc. to clarify the cause and give timely hemostatic treatment to prevent delay.