Black stool bleeding is more than 50ml, black stool is usually caused by gastrointestinal bleeding, in addition to some dietary factors, drug factors can also induce black stool. Gastrointestinal bleeding: such as peptic ulcer bleeding, cirrhosis, esophagogastric fundus varices rupture of veins, etc., when the amount of bleeding reaches 50-100ml, the blood in the digestive fluid decomposition of dark red or black, and discharged from the body to form black stools. Patients should seek medical treatment in time to identify the site of ruptured blood vessels, and stop bleeding through gastroenteroscopic clamping or the drugs norepinephrine and posterior pituitary hormone. Consumption of too much animal blood or vegetables containing too much iron such as spinach, taking ferrous sulfate, bismuth potassium citrate and other drugs, after digestion of the gastrointestinal tract will also show black stool. After stopping the consumption of such foods and drugs, the black stool manifestation gradually disappears. If patients have black stools, they should seek medical treatment immediately, complete gastroenteroscopy, blood test, blood pressure and other related examinations to determine the bleeding site and actively stop bleeding. Patients should not take medication on their own, so as not to delay the treatment and jeopardize the patient’s life.