Positive fecal occult blood is not necessarily bleeding, but may also be caused by consuming incompletely digested foods such as pig’s blood, duck’s blood, and large amounts of meat. At the same time, the test method can also affect the results. Positive fecal occult blood by immunoassay is usually gastrointestinal bleeding; positive fecal occult blood by chemical assay may be influenced by dietary factors. 1. Physiological: If you use the chemical method of fecal occult blood test, after eating pig blood, duck blood and other blood products before the examination of food, did not have time to fully digest, the results may be positive fecal occult blood, does not belong to the scope of the disease, no need for treatment. If the immunoassay fecal occult blood test is used, the test is for hemoglobin, and diet will not lead to positive fecal occult blood. 2. Pathological: common gastric ulcer, duodenal ulcer, inflammatory bowel disease, hemorrhoids, gastric cancer, rectal polyps and other causes can lead to positive fecal occult blood. It is necessary to further cooperate with the doctor to improve other examination items such as gastroenteroscopy, anoscopy, Helicobacter pylori test and other examination items, to clarify the cause of the disease, and timely treatment.