Black dots in the stool are considered to be caused by dietary factors, and may also be caused by peptic ulcer, intestinal polyps and other gastrointestinal diseases. 1. Dietary factors: eating some food with black spots, such as dragon fruit, black sesame, etc., will cause black spots in the stool; eating some iron-rich food, such as animal blood, etc., will also appear black spots in the stool. 2. Gastrointestinal diseases: peptic ulcer, intestinal polyps and other gastrointestinal diseases lead to gastrointestinal bleeding, especially old bleeding may also make the stool with black dots, can also have tar-like stool. When there are black dots in the stool, it is recommended to go to the hospital after excluding dietary factors, and then follow the doctor’s instructions to standardize the treatment after clarifying the cause of the disease.