N of 1 Study Design

Irritable bowel syndrome with diarrhea (IBS-D) is a functional gastrointestinal disorder, with characteristics of defecation related abdominal pain and diarrhea. Routine treatment strategy for IBS-D is symptom-based with unsatisfactory results, while there is a growing interest in complementary and alternative medicine such as Traditional Chinese Medicine. However, lack of high-quality evidences being the obstacle for its development. This study aims to evaluate the efficacy of Fengliao Changweikang Keli (FLCWK) on symptoms and health-related quality of life in mild to moderate IBS-D patients. After 2-week run-in period, each participant will be randomized to a sequence of six 4-week double-blind treatment periods of FLCWK 8 g three times daily or placebo, separated by 2-week washout periods.