The black stool is mainly considered to be iron-containing food or medication, as well as gastrointestinal bleeding, and the water-like stool is considered to be diarrhea, both of which together can lead to the above symptoms. Patients can go to the hospital to do colonoscopy, gastroscopy, routine stool examination and routine blood tests to clarify the cause of the disease and then targeted treatment. Common causes 1, dietary factors: pig blood, duck blood and other animal blood contains a large amount of iron, after eating these foods, iron is not fully absorbed by the body, in the intestine and sulfide combination, diarrhea may be discharged black water-like feces. In addition, if the food consumed is unclean, can also lead to the phenomenon of diluted black; 2, drug factors: anemia when taking iron supplements, such as ferrous gluconate, when there is diarrhea, there will be watery stools; 3, upper gastrointestinal bleeding: upper gastrointestinal bleeding is mainly due to peptic ulcer, acute erosive hemorrhagic gastritis and other diseases caused by the presence of diarrhea, alternating diarrhea and constipation, etc. performance, can appear black watery stools; 4, enteritis: the human body can appear black stools and watery stools when suffering from enteritis. Treatment measures and precautions 1. Patients should be careful not to continue to eat black food or iron in the near future, and should choose easily digestible food and avoid spicy, stimulating, cold, sticky and indigestible food to avoid increasing the burden on the stomach and intestines and aggravating the condition; 2. In addition to taking montelukast to stop diarrhea under the guidance of a doctor, patients should also have a gastroscopy to further clarify the cause of upper gastrointestinal bleeding or inflammation, and use infusion of isotonic Glucose, saline, plasma or other plasma substitutes should be used to replenish blood volume; 3. During diarrhea, attention should be paid to timely hydration to prevent water-electrolyte disorders due to dehydration, so as not to have adverse effects on health.