Common diseases include food protein allergy, gastrointestinal bleeding, bacterial dysentery and other diseases. 1. Blood in the stool and vomiting of blood are common in upper gastrointestinal bleeding, but the amount of bleeding depends on the height of the bleeding location and the length of time it stays in the intestine. If there is a lot of bleeding and the discharge is fast, it may appear dark red or bright red. 2, the lower gastrointestinal tract diseases are common hemorrhoids, anal fistula, anal fissure, rectal injury, bacterial dysentery, intestinal overlap, rectal tumors, etc.. This time it is mostly bright red or dark red, and if it stays in the intestine for a long time, black stools can appear. 3, esophagus, stomach and duodenum, biliary tract diseases can also lead to blood in the stool. 4, intestinal bleeding can not heal, serious infections, food protein allergies, side effects of drugs, acute infectious diseases and parasitic diseases can also cause intestinal damage and intestinal inflammation these can lead to blood in the stool. 5. Blood in the stool can also occur after eating hard food or swallowing a foreign body. Children with blood in the stool need to be examined for routine stool and colonoscopy to determine the type of disease based on the test results. Children with blood in the stool need to go to the hospital promptly for examination.