Blood in the stool for a long time indicates a persistent or recurrent bleeding lesion in the digestive tract. Tarry stools are often the result of upper gastrointestinal bleeding caused by malignant tumors of the stomach, peptic ulcers, biliopancreatic diseases, etc. Dark red bloody stools often indicate colon tumors and colon polyps. Therefore, if you have blood in your stool for a long time, you need to go to the hospital for gastroscopy, hepatobiliary, pancreatic and spleen ultrasound, small intestine microscopy, capsule endoscopy, enteroscopy and other related examinations to clarify the cause of gastrointestinal bleeding and perform targeted treatment as soon as possible.