Black stool the day after drinking is mainly caused by alcohol stimulation of the gastric mucosa leading to gastric mucosal erosion and bleeding, or caused by eating foods high in iron. Common causes 1, the normal situation: taking alcohol during the consumption of food or drugs containing high iron elements, will also cause the stool color black change, such as animal blood products, animal liver or iron, this is a normal phenomenon, no need to deal with; 2, disease factors: alcohol can destroy the gastric mucosa barrier, causing acute gastric mucosal lesions induced gastric bleeding. After bleeding, the blood will undergo a series of reactions in the intestine, forming black iron sulfide in the intestine, thus causing a change in the color of the stool. Treatment 1. Patients can first observe the condition, eat a light, easy-to-digest liquid diet, and try to avoid spicy and stimulating food. If the color of the stool is yellow or yellowish, it means that the gastric mucosa has been repaired and will not bleed, and the patient needs to do a good job of maintenance; 2. If the patient has continuous black stools, he needs to go to the gastroenterology department of the hospital for consultation, fecal occult blood test and gastroscopy, and a positive fecal occult blood test indicates that there is gastrointestinal bleeding, which requires symptomatic treatment with hemostatic drugs and stomach acid inhibiting drugs. Severe gastrointestinal bleeding also requires microscopic hemostasis.