Eating colon general bowel movements will not become black, black stools may be related to drug factors, upper gastrointestinal bleeding and other factors. 1. Drug factors: taking bismuth (such as colloidal bismuth pectin, etc.), iron supplements (such as ferrous succinate, etc.) can appear in the black stools, stop taking drugs can return to normal. 2. Upper gastrointestinal bleeding: such as gastric ulcer, duodenal ulcer, etc. can lead to gastrointestinal bleeding, hemoglobin in red blood cells in the intestinal tract under the action of bacteria and the reaction with chemicals, the formation of iron sulfide, which will lead to black stools. If you exclude medication and still have black stools, it is recommended that you consult a doctor in a timely manner to determine the cause of the illness under the guidance of a professional physician and follow the doctor’s instructions.