Diarrhea puddle of black water indicates the presence of diarrhea symptoms, generally due to gastrointestinal dysfunction, gastrointestinal tract inflammation infection caused, but the infection is mainly watery stools, will not appear black water-like changes. If you pull out a puddle of black water, on the one hand, it is caused by the consumption of black food or after consuming blood products, on the other hand, consider that it may be caused by gastrointestinal bleeding. Patients need to go to the hospital to do the relevant examination, differential diagnosis, and then take targeted treatment according to the cause. 1, eating animal blood products and iron-containing drugs: taking bismuth, iron or eating a lot of iron-containing food, such as pig blood, chicken blood, etc., the iron in the food will form ferrous sulfide in the intestine, diarrhea will appear to pull out a puddle of black water. If it is caused by the above reasons, you can first stop taking bismuth, iron, animal blood products under the guidance of a doctor, and then treat the symptoms of diarrhea; 2. Gastrointestinal bleeding: for example, gastric ulcer, duodenal ulcer or stomach tumor can cause gastrointestinal bleeding and accompanied by diarrhea symptoms, there will be a puddle of black water. It is recommended to check blood and stool routine at the hospital. Emergency rehydration and hemostatic drugs such as thrombin application are needed, and if necessary, minimally invasive intervention or surgical treatment is required.