Fecal occult blood ± (the stem of the question is eleven) refers to a weakly positive fecal occult blood test, suggesting that there may be a small amount of bleeding in the gastrointestinal tract, which can be seen in physiological causes, such as eating blood products, etc.; it can also be seen in peptic ulcers, acute gastric mucosal lesions, gastrointestinal tract malignant tumors, and other pathological causes. 1. Physiological causes: such as eating blood products, iron, such as ferrous sulfate, etc., can cause weak positive fecal occult blood. 2. Peptic ulcer: refers to the ulcer formed by self-digestion of gastrointestinal mucosa, which can cause gastrointestinal bleeding, and if the amount of bleeding is more than 5 ml, it can cause positive fecal occult blood. 3. Acute gastric mucosal lesion: a lesion characterized by different degrees of erosion, shallow ulceration and bleeding of gastric mucosa, which can also cause positive fecal occult blood. 4. Malignant tumor of digestive tract: such as gastric cancer, colon cancer, etc., which can also cause gastrointestinal bleeding, thus leading to positive fecal occult blood. There are many other causes of positive fecal occult blood, which should be taken seriously, consult doctor in time to find out the cause of the disease, and follow the doctor’s advice for further treatment or therapy.