Both infants and older children can experience constipation. Some constipation is caused by poor bowel habits, while others suffer from intestinal disorders. Therefore, parents should be aware that if their child has constipation for a long time without relief, they should go to the hospital promptly to see if the child has congenital megacolon or other diseases. First of all, we would like to briefly introduce the normal defecation process: defecation is a neurological reflex activity. The rectum is empty under normal circumstances, but when feces enters the rectum, the rectum fills up to a certain pressure, which can stimulate the receptors in the rectal wall and nearby receptors to produce nerve impulses, which cause contraction of the descending colon, sigmoid colon and rectum through a series of nerve conduction, and the sphincter inside and outside the anal canal to stretch, so that the feces is expelled from the body. In normal people, the rectum has a certain threshold for pressure stimulation of feces, and when this threshold is reached, the urge to defecate is generated. However, the final decision to defecate depends on whether the action of the higher defecation centers on the lower centers is inhibited or enhanced. The frequency and habit of defecation varies from person to person, usually once a day, after breakfast. Some people have a bowel movement once every 2 to 3 days, but they do not feel any difficulty in defecating. After defecation, there is a comfortable and pleasant feeling. Functional constipation: The most common type of constipation is habitual constipation caused by poor bowel habits of the child. These children initially have normal bowel movements, but when the child’s life is irregular or the normal routine changes, for example, when the child is playful, or when the child has just started kindergarten or school, the child also goes to defecate when the child has the intention to defecate, which over time causes the normal defecation reflex to weaken or disappear, and the pressure stimulation threshold of the rectum to feces rises, and the feces stays in the intestine for too long, causing excessive absorption of water, resulting in dry stools and more difficult elimination. It is more difficult to eliminate. In addition, some children have unreasonable dietary habits or structure. For example, children who are paranoid eaters consume too little coarse fiber food and only some fine food, resulting in weakened intestinal peristalsis, which can also cause feces to stay in the intestine for too long, resulting in dry stools and constipation; in addition, some children eat less, producing less feces, and the feces in the rectum does not reach the pressure to produce stool, and constipation occurs. Treatment should find the cause. Correct bad bowel habits, remind or train children to have regular bowel movements. Pay attention to adjusting the diet structure and encourage the child to eat more vegetables and fruits and exercise more. Do not let the child read books or TV to distract him/her during bowel movements, and do not sit on the toilet for too long. Occasionally, when the stool is dry, you can use a laxative such as corky to help defecate. Pathological constipation: This refers to constipation caused by disease. The most common type of constipation in children is constipation caused by congenital megacolon. Next, attention should be paid to constipation caused by anal stenosis, pelvic or perirectal tumor compression, and urinary retention. Congenital megacolon (Hirschsprung′s discase) is a common congenital intestinal malformation in children due to persistent spasm of the rectum or distal colon and stagnation of feces in the proximal colon, causing hypertrophy and dilatation of the intestinal canal. It is a common congenital intestinal malformation in children, with a male to female ratio of 4:1 and a genetic predisposition. The basic pathological change of congenital megacolon is the absence of ganglion cells in the intermuscular and submucosal plexus of the intestinal wall and the increase in the number and thickness of unmyelinated parasympathetic nerve fibers, hence the name “aganglionosis”. Due to the absence and reduction of ganglion cells, the diseased intestinal segment loses propulsive normal peristalsis and is often in spasm, forming functional intestinal obstruction and difficulty in passing feces. In addition, the presence of ganglion or plexus in the intestinal wall, but the morphology and function are abnormal, which also manifests as persistent constipation, and this kind of disease becomes the mega colon type of marginal disease. More than 90% of children with congenital megacolon have no fetal stool within 36 to 48 hours after birth, and later have a history of intractable constipation and abdominal distention that requires enemas, laxatives or anal suppositories for defecation. There is often malnutrition, anemia and loss of appetite. The abdomen is highly distended and a wide intestinal pattern is seen. Rectal palpation reveals a hollow rectal jug abdomen where stool cannot be palpated, beyond the spastic segment to the dilated segment where stool can be palpated. Severe cases can be accompanied by small intestine colitis, children with severe abdominal distension, vomiting and sometimes diarrhea, due to diarrhea and the accumulation of large amounts of intestinal fluid in the enlarged intestinal canal, resulting in dehydration acidosis high fever, rapid pulse and decreased blood pressure, if not treated in a timely manner, can cause a high mortality rate. In addition to the typical history and signs, the diagnosis needs to be clarified with the help of barium enema or biopsy. Clean bowel washing is very important in the treatment of megacolon. Temporary conservative treatment of newborns as well as preparation for surgery of children requires clean bowel. Cleansing removes accumulated stool, reduces absorption of toxins, and enables children to eat normally, which is beneficial for maintaining their nutrition. If the child can be diagnosed early and treated surgically, the immediate and long-term postoperative results are more satisfactory. At present, we use the world’s most advanced transanal megacolon or laparoscopic-assisted transanal megacolon radical surgery, which is less traumatic, faster recovery, no large scar in the abdomen as in previous surgical methods, and almost no risk of intestinal adhesions. Many children have already recovered. Constipation can also occur due to anal stenosis and abnormal anal position, which requires anal dilation or surgery. It should be noted that constipation due to sacrococcygeal tumor compression can easily be misdiagnosed and can be clearly diagnosed by anoscopy. In conclusion, there are many causes of constipation in children, which should not be ignored by parents, and timely examination in pediatric surgery is very necessary for children with frequent constipation.