Food therapy can treat functional constipation. Constipation is defined as having less than three bowel movements per week, dry stools, and difficulty in defecation, and is the result of a combination of factors. According to its etiology can be divided into organic constipation and functional constipation, organic constipation refers to the digestive system lesions and drugs and other causes, such as congenital megacolon, inflammatory bowel disease. The cause of functional constipation is not clear, and may be related to bowel habits, dietary habits and exercise habits. The treatment of constipation requires comprehensive treatment, including lifestyle modification, medication and surgery. Lifestyle adjustment mainly includes dietary fiber supplementation, which is the preferred and effective treatment method, especially for functional constipation. Its mechanism of action is to promote intestinal peristalsis so that the stool can be easily discharged. Foods with high fiber and high water content include banana, radish, celery, coarse grains and so on. The treatment of constipation needs to be carried out under the guidance of a professional doctor, do not use medication privately, which may cause danger.