In children with bleeding stools, if there is no obvious abdominal pain, bloating, nausea, vomiting, or fever, it is important to look at whether the blood is on the surface or inside the stool. If the blood is on the surface of the stool, consider that lesions above the rectum, colon and around the anal canal are more likely, such as anal fissure; if fresh blood is mixed inside the stool, it suggests lower gastrointestinal bleeding. At this time, it is recommended to go to the anorectal department, or gastroenterology department to perform colonoscopy and proctoscopy to further clarify the diagnosis. If the baby’s stool is black or dark red, you need to be alert to upper gastrointestinal bleeding, where the blood passes through the digestive tract and the iron inside is oxidized layer trivalent iron and appears black. If the baby is cooperative, gastroscopy can be perfected. If none of the above examinations reveal obvious abnormalities, attention should also be paid to the presence of small bowel disease. Of course, not all red material in the stool means there is blood. Some babies have red residue in the stool after eating chili peppers and beets, which also looks like blood, but it is not. Green leafy greens, blood tofu, and iron supplements, all of which are rich in iron, can turn your baby’s stool black because the iron is oxidized and turns black. If parents notice black or red stools, they can take their baby’s stool to the hospital for a lab test for fecal occult blood to clarify if there is a bleeding problem.