Whether an occasional black stool is important or not cannot be generalized. Physiological black stools do not require excessive concern, while black stools caused by pathological factors require great attention. The causes of black stool include physiological and pathological. If it is caused by taking iron, animal liver, animal blood or red heart dragon fruit and other foods and medicines, it is a normal physiological phenomenon and no special treatment is needed. If the patient does not eat food that can lead to physiological black stool, pathological factors are considered, which can be seen in upper gastrointestinal bleeding caused by hemorrhagic gastritis, gastric ulcer, colitis, duodenal bulb ulcer, gastric cancer, etc. Patients should pay high attention to this and promptly go to the gastroenterology department to improve the stool routine and fecal occult blood tests to clarify the diagnosis. In the daily diet, patients need to focus on light and easily digestible food and avoid spicy and stimulating food to avoid increasing the burden on the gastrointestinal tract.