The appearance of bloody stools usually indicates some diseases, including upper and lower gastrointestinal tract diseases, as well as intra-abdominal vascular blockage diseases, which may cause bloody stools, and need to go to the hospital for occult blood test to clarify the cause. When bleeding occurs in the stomach and esophagus, when the amount of bleeding is large, it will appear as dark red blood stool after discharge from the anus. Stimulation, prolonged rectal irritation may trigger bloody stools; 3, intra-abdominal vascular blockage diseases: such as the formation of portal vein thrombosis, when the blood circulation is poor, it will cause thrombosis, and when the thrombus blocks the blood vessel, strangulation and necrosis will easily occur, which leads to severe abdominal pain and bloody stools. Clinically, bloody stools can be bright red or dark red, and cannot be diagnosed as a certain disease only by virtue of bloody stools.