Constipation is the most common complaint in childhood gastrointestinal disease,affecting an estimated 20% of the global children.The treatment strategies consist of diet control,behavioural intervention and oral and sometimes rectal laxatives. Given higher success rate and fewer side effects,the laxative PEG3350 has been considered the first choice in childhood constipation.However, effectiveness of PEG 3350 laxative is not lasting, additional treatment interventions are still necessary.With an unsatisfactory response to current treatments, many patients seek help from Chinese Herbal Medicine.In view of the traditional theory, childhood constipation is derived from weakness of gastric and splenic function.The functional weakness is characterized by food stagnation and further pathological heat accumulation in the gastrointestine. The food stagnation can slow the gastrointestinal motility while heat causes constipation by drying the intestines and their content. Therefore, the therapeutic principles and practices for childhood constipation must focus on the pathophysiological basis accordingly. In the documented traditional medicine dictionary(Pi Wei Lun), Xiaojidaozhi Decoction is well described in improving the gastric and splenic function, eliminating food stagnation and removing pathological heat accumulation, and it has always been used in treatment of constipation throughout Asia since the first description in Pi Wei Lun in 1249. It comprises twelve herbs. Through the combined action of these herbs, Xiaojidaozhi Decoction can increase fluid in the intestines and facilitate the gastrointestinal motility, relieving the symptoms of constipation. Despite of the long history of successful use of Xiaojidaozhi Decoction in childhood constipation, a large randomized placebo-controlled trial is still not available.The aim of this study was to explore the clinical efficacy and safety of Chinese herbal medicine Xiaojidaozhi Decoction in the treatment of childhood constipation.

Inclusion Criteria:

1. Clinical diagnosis of childhood constipation
2. Criteria of constipation meets the Rome IV criteria(H3a)
3. Must be able to swallow capsules

Exclusion Criteria:

1. Digestive tract diseases
2. Neurologic diseases
3. Endocrine diseases
4. Metabolic diseases
5. Gastrointestinal surgery
6. Using drugs which can take impact on bowl motility