Generally, a positive fecal occult blood indicates a GI bleeding of 5 ml or more. If the gastrointestinal bleeding reaches 50 ml or more, the stool will show a change in color, such as black or bloody stools. A positive fecal occult blood indicates bleeding in the GI tract and it is best to undergo a formal examination such as gastroscopy or colonoscopy. Bleeding in any part of the GI tract will show positive fecal occult blood. For example, in the stomach, such as gastric ulcer, duodenal ulcer and gastric cancer, all will show positive fecal occult blood. For the colon, colon cancer and inflammation of the colon will also show positive fecal occult blood, especially for the elderly, positive fecal occult blood is a very meaningful test, do not miss the disease, go to the hospital for examination in a timely manner. In addition, if you have recently eaten food with blood, such as pig’s blood or duck’s blood, you may also have positive fecal occult blood, which needs to be identified, and in this case, you should review it regularly.