Stool occult blood is usually done first, and there is a stool occult blood item in the stool routine, you must remind the doctor who issued the test to check the occult blood test, if the occult blood test indicates positive, you can clarify the stool occult blood. If the occult blood test is positive, the occult blood in the stool can be confirmed. If the occult blood in the stool is clear, it is necessary to further clarify what causes the occult blood in the stool. If the stool is positive for occult blood, it is common to have chronic gastrointestinal bleeding, such as whether it is combined with colon polyps, if there are more or larger colon polyps, occult blood may also appear in the stool. If there is a combination of peptic ulcers, including gastric ulcers or ulcers in the duodenal bulb, if there is a small amount of chronic small-vessel blood leakage, it can also appear positive for occult blood in the stool, and more importantly, it is mainly to exclude tumors in the digestive tract, such as tumors in the stomach or intestinal tract, which can appear positive for occult blood in the stool. It is crucial to clarify whether the positive occult blood in stool is combined with ulcer or tumor. After the positive occult blood is confirmed, further gastroscopy, including colonoscopy, should be performed to clarify the location of the bleeding before we can rest assured.