The fecal occult blood test is usually performed once, usually in a regular hospital to make it more clear whether there is bleeding, if you suspect the results can be checked two to three times more to determine whether there is bleeding and the approximate amount of bleeding. Fecal occult blood test is mainly to take some fecal specimens for examination, used to assist in determining whether the patient has gastrointestinal bleeding. The fecal occult blood test is normally negative, but when the amount of upper gastrointestinal bleeding reaches 5 ml, a positive fecal occult blood test will occur. Animal liver, blood products and iron-containing foods, green vegetables, etc. are prohibited for three days before the fecal occult blood test is performed to avoid interfering with the test results. If the test is false positive due to some dietary reasons and you doubt the authenticity of the result, you can have it checked again. Fecal occult blood test should be examined in regular hospitals, and positive occult blood test should be treated under the guidance of doctors.