The causes of bleeding stools in infants are divided into two main categories, one is gastrointestinal diseases and the other is caused by systemic diseases. Gastrointestinal diseases are: first, diseases that may lead to blood and mucus in the stool, including bacterial dysentery, amoebic dysentery, and toxic dysentery, which are caused by infections and can have fever, abdominal pain, increased stool frequency, and fresh blood and mucus in the stool. There is also acute necrotizing enterocolitis, also known as acute hemorrhagic enterocolitis, with fever, abdominal pain, abdominal distention, vomiting, and also stools with mucus, bloody stools, or stools like adzuki bean soup, wash water-like, fishy smelling stools. Then there is intestinal entrapment, mostly seen within 2 years of age, especially 4-10 months old babies also appear this situation; second, milk protein allergy, stool with blood or blood clots, this child mostly have eczema, family history of allergic diseases; third, stool like tar color for peptic ulcers, or nose bleeding after swallowing through the stool discharge; fourth, fresh blood dripping out after stool, may be anal fissure or rectal polyps. Anal fissures are mostly accompanied by constipation and dry stools. Anal fissures are easily seen, while rectal polyps need to be diagnosed by proper instrumentation at the hospital. Some systemic diseases can also cause bleeding in the stool in infants, but they are not common.