There are two possibilities for chocolate colored stool: First, it is related to diet. If you eat food with color, such as pig’s blood, sheep’s blood or oral ferrous sulfate, you can have a change in color or chocolate colored stool. Second, there may be gastrointestinal bleeding, if there is a gastric ulcer or duodenal bulb ulcer, or acute erosive bleeding gastritis, or inflammatory bowel disease, ulcerative colitis, can show blood in the stool, some show chocolate color, some coffee-like color, and some can show mucus-like black stool or tar-like black stool. If there is positive occult blood and red blood cells with a plus sign, most of the diagnosis is gastrointestinal bleeding, and gastroscopy and colonoscopy should be done to further clarify the diagnosis.