The absence of bowel movement for three days in a four-year-old child can be due to pathological conditions (e.g. functional constipation), physiological phenomena, etc. Intervention needs to be decided according to the cause, e.g. functional constipation requires intervention with the use of an opioid, if necessary. 1. Pathological conditions: For children who have had regular daily bowel movements, the above phenomenon, partly accompanied by dry stools and difficulty in defecation, is considered functional constipation, and some children may have bloody stools or abdominal discomfort as a result. Interventions such as lubrication of the intestinal tract with corkscrews to facilitate bowel movement, oral microecological agents (e.g., Clostridium Typhimurium) or laxatives (e.g., Lactulose), as well as a sensible diet should be evaluated by a physician. 2. Physiological phenomenon: If the child used to defecate once every 2~3 days, and the bowel movement is regular and smooth, the above phenomenon may be a normal physiological phenomenon, which does not need special intervention for the time being, but need to continue to observe, pay attention to drink more water and increase dietary fiber intake. Four-year-old children who have not had a bowel movement for three days are advised to consult a specialist for evaluation and intervention. The above medications should be used under medical supervision.