Brownish-black stools can be found in the following situations:1. Bleeding in the gastrointestinal tract, such as bleeding in the duodenum and stomach, the bacteria in the intestines will react with the iron in the red blood cells in the gastrointestinal tract and form iron sulfide, resulting in brownish-black stools.2. Some digestive disorders, such as duodenal ulcers, enteritis, gastric ulcers, gastritis, etc., can lead to brownish-black stools with a bloody odor.3. Certain foods cause Some foods, such as animal blood and animal liver, etc., the iron in these foods will react with the bacteria in the intestines to produce black iron sulfide, and the stool will become brownish-black. 4, some drugs, such as activated charcoal, iron supplementation drugs, etc., these drugs have a staining effect, which will also lead to brownish-black stool, but this is normal, do not worry, stop taking the drug after the stool color will be The color of the stool will return to normal after stopping the medication.