Black poop is black stool. Drinking white porridge usually does not cause black stool, and it is considered to be related to other diets, medications, and upper gastrointestinal bleeding disorders. 1. Other diets: If the patient consumes blood products or animal liver at the same time during the drinking of white porridge, it may lead to black stools, which usually does not need to be treated. 2. Drugs: if patients have recently taken bismuth potassium citrate, bismuth pectin and other gastric mucous membrane repair agents, ferrous succinate and other iron agents, in the intestinal tract by the digestive juices digestive decomposition, metabolites are black, so the manifestation of black stools; 3. Upper gastrointestinal bleeding: if you suffer from peptic ulcer, gastric cancer and other gastric diseases, gastric mucosa and gastric blood vessels can be damaged during the acute attack triggering upper gastrointestinal bleeding. It can be manifested as tarry black stool. Patients may also experience loss of appetite, stomach pain, bloating, vomiting, vomiting blood and clinical manifestations such as fatigue and dizziness. There are many possible causes of black stools, and it is recommended that patients actively go to the hospital to confirm the cause of the disease and follow the medical advice.