It is normal to have black stools after eating chocolate. If you have an upset stomach and black stools, it is considered to be due to gastrointestinal bleeding and should be examined promptly. If the black stool is caused by eating iron, activated charcoal, animal blood, chocolate and so on, this is a normal phenomenon. Therefore, when black stools appear in the clinic, the first thing to do is to clarify whether it is due to gastrointestinal bleeding or due to food. In case of gastrointestinal bleeding, the black stools are tarry and should be examined routinely, and if there are red blood cells, it is necessary to do further colonoscopy and gastroscopy. Repeated black stools should be timely to the hospital, the doctor to clarify the cause of the disease, and then give targeted treatment. If it is not detected in time, it may seriously threaten the patient’s life and health and quality of life.