To diagnose gastrointestinal bleeding, patients can be diagnosed by both fecal occult blood tests and gastrointestinal endoscopy. In the case of bleeding in the digestive tract, the stool will show positive occult blood during the test and the site of bleeding in the digestive tract can be seen through the gastrointestinal endoscopy. It is important to avoid eating meat, liver and blood sausage for three days before the endoscopy to avoid affecting the results. In addition, routine blood tests can also check whether a patient has gastrointestinal bleeding. During the routine blood test, due to bleeding in the body, there is a rapid increase in white blood cells and platelets in a short period of time due to blood loss stress, which can determine that the patient has gastrointestinal bleeding. In addition, in order to improve the accuracy of the examination, patients can also undergo ultrasound examination and arteriography to assist in the diagnosis.