The Efficacy and Potential Mechanisms of Chinese Herbal Medicine on Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is one of the most common functional bowel disorders (FBD), which is characterized by recurrent abdominal pain, abdominal bloating/distention associated with defecation or changed bowel habits. Currently, there is no evidence of obvious anatomic or physiologic abnormalities on the routine diagnostic examinations. There are multiple pathological factors involved in IBS responsible for its heterogeneous nature, although the exact etiology and pathology of IBS are not well known and it is disappointed to develop biomarkers for this disorder. These factors including low-grade inflammation, activation of immune system, changed intestinal microorganism, small intestinal bacterial overgrowth (SIBO), malabsorption of bile acid (BA), increased number of mast cells (MCs). Current pharmacologic treatment for IBS focuses on alleviation of its symptoms, but not on the elimination of its cause. Although there are a lot of conventional chemical medicines for IBS available, due to the limited clinical benefits, high medical expenses and severe side effects, many IBS patients have turned to alternative medicine, particularly Chinese herbal medicine (CHM). Chinese herbal therapies have been used for thousand years in eastern Asia and have been provided that they are effective in relieving symptoms among IBS patients. Generally, traditional Chinese herbal formulae (CHF) consisting of CHM can be easily adjusted in accordance with concrete conditions, which means the treatment is based on syndrome differentiation and varied from individual to individual. Meanwhile, CHF/CHM containing many different ingredients may act on multiple sites/pathways with potential synergistic effects and chemical reactions.