Functional constipation is a high morbidity disease. The life-long treatment of functional constipation can seriously impact a patient's quality of life. At present, one of the most frequently used treatment is catharsis, which deals with the symptom. There are three main problems with catharsis. First, there are no long-lasting effects once the patient stops taking medication. Second, there are many side effects, including abdominal pain with defecation and diarrhea. Third, long-term use of irritant laxatives will not only make the constipation become refractory and complex; but also, this type of medicine can harm the enteric nervous system, cause melanosis coli, or even carcinoma of colon. Therefore, a therapy that is safe with minimal side effects and good short-term and long-term effects is urgently needed in functional constipation treatment.