In the pediatric surgery clinic, I often encounter many children with blood in their stools. The word “blood in the stool” is simple to say, but the causes are really varied. It can be a medical or surgical disease, and sometimes it can be a false sign, such as eating certain foods that contain pigments, which needs to be carefully analyzed. The common internal blood in stool is enteritis and bacterial dysentery. Children mostly have a history of unclean diet and are accompanied by gastrointestinal symptoms such as nausea, vomiting, abdominal pain, etc. Some children may have high fever and systemic infection symptoms, so the possibility of bacillary dysentery is high. Routine fecal examination and fecal culture are valuable for diagnosis. Upper gastrointestinal bleeding may appear as tarry stools, and short-term heavy bleeding may also result in fresh blood. Bleeding from ruptured esophagogastric fundic veins or biliary bleeding due to cirrhosis, portal hypertension, and gastroduodenal ulcers can also present with blood in the stool. Common pediatric problems caused by surgical problems include anal fissures, rectal and colonic polyps, Michael’s diverticulum, and intestinal duplication malformations. Congenital megacolon combined with small bowel colitis can also present with bloody stools. The more characteristic blood is the jam-like stool after intestinal overlap, which is most common in infants aged 4-10 months. The onset of crying is paroxysmal, and during the quiet period it is as usual, but the crying becomes more and more violent and the interval is shortened, with jam-like stools appearing after an average of 12 hours. In older children, the presence of intussusception is usually due to other lesions of the intestinal canal itself, such as congenital malformations or tumors. Blood in the stool in children should be taken seriously by their parents, and early medical attention is very important.