The statement that there are seven reasons for the appearance of black stools is clinically incorrect. There are many reasons for the appearance of black stools, which may be caused by physiological factors, medications, and pathological factors such as peptic ulcers, colon cancer, and blood disorders. 1. Physiological factors: for example, eating pig’s liver, pig’s blood, chocolate, spinach, purslane may lead to black stools. This in turn triggers the phenomenon of black stool color. 2. Drug factors: such as taking iron, bismuth potassium citrate, etc. can appear black stool. 3. Pathological factors (1) Peptic ulcer: when the blood vessels at the bottom of gastric ulcer or duodenal ulcer rupture, upper gastrointestinal bleeding may occur. The stomach and duodenum are far away from the anus, and the blood stays in the intestinal tube for a long time, which may lead to black stools. (2) Colon cancer: when the tumor tissue of colon cancer is necrotic and detached and discharged with feces, or when the blood vessels of intestinal wall are eroded, it can lead to gastrointestinal bleeding, and black stool is formed by mixing the blood and feces. (3) Blood disease: for example, leukemia, hemophilia, thrombocytopenia, etc. can also cause gastrointestinal bleeding, resulting in black stool in the morning. In addition, the causes of black stool also include intestinal tuberculosis, intestinal typhoid fever, bile duct stones, gallbladder cancer, etc. If the symptoms of black stool appear for a long time, you should go to the hospital in time to improve the examination, and give targeted treatment after clarifying the cause of the disease.