If a patient with cancer has black stool, it only indicates that the patient currently has gastrointestinal bleeding and does not mean that the cancer is terminal, so please rest assured. For cancer combined with bleeding, that is, gastric cancer combined with bleeding is very common, because the surface of cancer can occur erosion and ulcer, so it is easy to invade blood vessels and cause upper gastrointestinal bleeding. If upper gastrointestinal bleeding occurs, the first clinical manifestation is black stool, including bleeding caused by other benign gastric diseases, such as gastric ulcer and bleeding, bleeding caused by acute erosive hemorrhagic gastritis, and bleeding from ruptured esophagogastric fundic varices. If the patient has black stool, it is recommended to go to the hospital promptly and cooperate with the doctor to use drugs to suppress acid and stop bleeding, if necessary, you can also cooperate with the doctor to perform electronic gastroscopy to help clarify the diagnosis, and may also need to perform microscopic hemostasis treatment, etc., the specific need to consult the specialist.