Positive fecal occult blood is not normal. Positive occult blood is considered to have the possibility of gastrointestinal bleeding, which is divided into upper, middle and lower gastrointestinal bleeding. If there is only positive fecal occult blood and no blood in the stool that appears to the naked eye, it can be considered that the amount of bleeding is around 50 ml, and it is generally considered that there is damage to the mucosa, such as the result of peptic gastric ulcer, duodenal ulcer or inflammatory bowel disease. If the stool is positive for occult blood and the stool is dark, tarry black or dark red, most of the bleeding is considered to be 200 ml or more, which is usually the result of active gastrointestinal bleeding, such as bleeding from ruptured esophagogastric fundic varices or bleeding caused by ruptured blood vessels in the gastrointestinal tract. In this case, if the stool is positive for occult blood, gastroscopy and colonoscopy should be performed to further assist in the diagnosis and treatment.