Functional constipation refers to constipation that is not caused by organic factors. According to the Rome III classification, the diagnostic criteria vary by age. 1.Diagnostic criteria for functional constipation in children younger than 4 years old: at least 2 of the following conditions are met and persist for 1 month. (1) 2 or less bowel movements per week; (2) at least 1 bowel incontinence per week after being able to defecate on their own; Jiang Mifu, Department of Gastroenterology, Children’s Hospital, Zhejiang University School of Medicine; (3) history of large amount of fecal retention; (4) history of painful or difficult defecation; (5) large fecal mass in the rectum; (6) fecal matter so large that it blocks the toilet drain. 2.Diagnostic criteria for functional constipation in children older than 4 years old: 2 or more of the following, with symptoms at least once a week for at least 2 months, but excluding irritable bowel syndrome (1) 2 or less bowel movements per week; (2) at least 1 bowel incontinence per week; (3) history of massive fecal retention or posture associated with fecal retention; (4) same diagnostic criteria as for children under 4 years of age. Treatment is based on dietary modification (e.g., large amounts of water, high-fiber foods, fruits, etc.), supplemented by medication (e.g., soluble laxatives, osmotic laxatives, digestive aids, probiotic preparations, and proprietary Chinese medicines). If the rectal-anal power function test suggests anal sphincter dysfunction coordination, biofeedback therapy can be performed (for children older than 4 years old).