Patients with gastroenteritis can have black stools. Some patients may have vomiting that is more violent and may cause tears in the mucosa of the cardia or damage to the throat. Some blood components can reach the stool with the digestive tract, and in combination with the excretion of stool, black stool can appear. Some patients may have serious diarrhea, diarrhea, abdominal pain for a long time, causing some stimulation to the intestinal mucosa, or damage to the intestinal mucosa capillaries, bleeding, mixed with the stool, can also appear black stools during defecation, gastroenteritis can appear black stools, it is recommended that if the vomit is more intense or diarrhea is more serious patients, must go to the emergency department or gastroenterology It is recommended that patients with severe vomiting or diarrhea should go to the emergency department or gastroenterology department for relevant examination and treatment. The blood electrolytes and fecal occult blood must be checked, and the situation can be treated with drugs that replenish electrolytes, antibiotics, mucosal protection, and drugs that inhibit gastric acid and promote recovery, which can gradually recover after a period of medication.