Constipation is a common symptom of the digestive system, where stool stays in the colon for too long and becomes dry and hard because of the reduced water content, making it difficult to pass. The definition of constipation is based on the shape of the stool, the frequency and the degree of difficulty in defecation. A normal child who has stools once every 2-3 days without difficulty should not be considered constipated. Generally speaking, a hard stool with difficulty in defecation more than once every 3 days is considered constipation. According to the Rome III diagnostic criteria, constipation is considered in children under 4 years of age with at least 2 of the following: 1. 2 or fewer bowel movements a week; 2. incontinence at least once a week; 3. a history of fecal retention; 4. a history of hard stools; 5. stools causing toilet blockage. Children ≥4 years of age must meet 2 or more of the following for a diagnosis of constipation: 1. ≤2 bowel movements per week in the toilet; 2. at least 1 bowel incontinence per week; 3. history of holding position or excessive restraint in defecation; 4. history of painful or difficult defecation; 5. presence of large fecal masses in the rectum; 6. large fecal masses that have blocked the toilet. The above criteria were met at least 2 months prior to diagnosis, with at least 1 episode per week. The clinical manifestations of constipation are dry, hard stools, difficult to pass, and less frequent bowel movements. Some children often have a history of decreased bowel movements before developing constipation. Sometimes the feces may cause bleeding of the intestinal mucosa, resulting in a small amount of blood or mucus on the surface. Pain in the anus during defecation can cause external hemorrhoids in severe cases. Chronic constipation often loss of appetite, resulting in malnutrition over time, more constipation. Sometimes children with constipation often have the intention to defecate but can not be clean, and the number of stools increased. In severe constipation, the stool is locally embedded, and may not be consciously from the dry stool around the flow of intestinal secretions, like fecal incontinence. The classification of constipation varies according to its basis. If there is no organic lesion in the gastrointestinal tract and constipation occurs, it is called functional constipation or idiopathic constipation. If there is an organic lesion, it is called organic or secondary constipation. Constipation occurs due to the inability of the smooth muscle contraction of the colon and rectum in a flaccid state, and becomes flaccid constipation. If constipation occurs due to smooth muscle spasm, it is called spastic constipation. If the stool is retained in the colon, it is called colonic constipation. If retained in the rectum, called rectal constipation. Etiology 1, secondary constipation: (1) organic diseases of the gastrointestinal tract: congenital megacolon, anal fissure, anal-rectal stenosis, anal constriction, anal prolapse, etc. (2) Neurological disorders: psychomotor retardation, myotonic dystrophy, spinal injury, spina bifida or tumor compression of cauda equina, congenital muscle weakness, etc. (3) Metabolic factors and metabolic diseases: dehydration, hypokalemia, hypercalcemia, cystic fibrosis (fetal fecal intestinal obstruction), hypothyroidism, diabetes mellitus, porphyria, etc. (4) Some drugs: opioids, atropine and related antispasmodics, antidepressants, psychosuppressants, anticonvulsants, calcium channel inhibitors, vincristine derivatives, diuretics, iron, etc. (5) Some heavy metal poisoning such as lead poisoning can also have constipation. 2, functional constipation: (1) insufficient diet: infants eat too little, digestion, liquid absorption, residual residue less, resulting in reduced stool, thickening. When the amount of sugar in milk is not enough intestinal peristalsis is weak, can make the stool dry. (2) improper food composition: the nature of the stool is closely related to the composition of food. Food contains a lot of protein and carbohydrates, intestinal fermentation process less, the stool is easy to alkaline, dry; food contains more carbohydrates, intestinal fermentation bacteria, fermentation, more acid production, stool is easy to acidic, more often and soft; such as food fat and carbohydrates are high, the stool is moistened. Children’s partial diet, many children like to eat meat, eat less or do not eat vegetables, too little fiber in the food, also prone to constipation. (3) intestinal malfunction: irregular life and lack of regular bowel training, has not formed the conditioned reflex of defecation, school-age children often because no early morning bowel habits, and learning time can not be ready to defecate, lame in class, laxative abuse or abuse of enemas, colonic weakness, rectal compliance abnormalities, anal sphincter synergism disorder (anismus), etc., can lead to constipation. (4) Mental factors: sudden mental stimulation, or sudden change of environment and living habits can cause short time constipation. Assessment 1. Take a detailed medical history to understand the exact stool pattern, ask about the duration of symptoms, frequency of defecation, stool properties (volume, shape, hardness, whether blood is present), ease of defecation, whether defecation is accompanied by pain, whether other symptoms of the gastrointestinal tract (abdominal pain, bloating, vomiting, growth disorders, etc.); understand the presence of endocrine, metabolic and neurological diseases; understand the presence of symptoms of anorectal local lesions. Have any special medication history. 2.Pay attention to the perineum and perianal area during physical examination and perform finger examination/notice the presence of anal fissure, skin infection and diaper rash. 3, diagnostic tests (1) Diagnostic tests should be performed selectively. Laboratory tests can detect the primary cause of constipation, such as hypokalemia, hypothyroidism, etc. Only when there are positive findings in the history and physical examination are relevant laboratory tests required. (2) Suspected anorectal organic pathology is feasible anoscopy, colonoscopy, barium enema examination. (3) If functional constipation is considered, first try to increase food fiber intake, change poor dietary habits, etc. If this fails, then perform functional measurements, such as anorectal manometry, fecal imaging, colonic operation detection, etc.