Juvenile polyps are pathologically diagnosed as well-differentiated but irregularly sized glands with mature glandular epithelial differentiation without heterogeneous hyperplasia and a large amount of granulation tissue in the interstitium, with varying degrees of cystic expansion of the glands and fluid storage, so they are also called mucinous or retention polyps. They are intestinal misshapen polyps, which occur in more than 90% of children and can also develop in adults. Juvenile polyps are the most common cause of lower gastrointestinal bleeding in children, mostly solitary and located in the rectum and sigmoid colon, but there are also multiple polyps located in the proximal large intestine. The etiology is still unclear, and there are five main speculations: 1. chronic inflammatory stimulation: chronic inflammation of the intestine causes ulceration of the local mucosa, formation of connective tissue or granulation tissue, and hyperplasia of the epidermis, glandular epithelium and submucosal tissue; 2. chronic mechanical stimulation: long-term stimulation by non-inflammatory factors such as hard stool and intestinal parasites leads to limited hyperplasia of the mucosa, glandular epithelium and submucosal tissue; 3. embryonic tissue ectopic: refers to the organism The normal tissues in an organ are arranged in the wrong combination during development and form lesions; 4, viral infection; 5, genetic factors. Painless hematochezia is the main manifestation. The blood in the stool is repeated, and it occurs at the end of defecation, mostly on the surface of the stool with a strip of bright red blood, which does not mix with the stool. In a few cases, there are several drops of blood from the anus after defecation. The polyp may suddenly fall off and bleed profusely. When there is secondary infection on the surface of the polyp, there is a small amount of mucus and pus in addition to blood in the stool. The child usually has no pain during defecation. High polyps may cause abdominal pain or even intestinal entrapment due to obstruction of bowel movement or traction of the stalk on the intestinal wall. Low polyps can be pushed out of the anus during defecation, and a red round mass can be seen at the anus, which can become embedded and necrotic if not sent back in time.