Effect of herbal extract granules combined with probiotic mixture on irritable bowel syndrome with diarrhea: study protocol for a randomized controlled trial.

Irritable bowel syndrome (IBS) is a chronic gastrointestinal disorder characterized by abdominal pain and change of bowel habits without organic disease. Many patients seek alternative IBS treatments because of the limitations of conventional treatments. Gwakhyangjeonggisan (GJS), a herbal formula, has long been used for alleviating diarrhea-predominant IBS (D-IBS) in traditional medicine. Duolac7S, which comprises 7 bacterial species as probiotics, has been frequently used for D-IBS. Although GJS and Duolac7S have been administered simultaneously in many D-IBS patients, no study has investigated the effects of GJS and Duolac7S combination therapy on D-IBS. The current trial is a randomized, double-blinded, placebo-controlled, 4-arm study. After a 2-week run-in period, 60 patients with D-IBS will be randomly assigned to one of the 4 combination groups consisting of GJS (water extract granules, 3 g/pack, 3 times a day) with Duolac7S (powder form, 1 capsule, 2 times a day) or their placebos and followed up for 2 weeks. The assigned treatments will last for 8 weeks. The primary outcomes are adequate relief of IBS pain and discomfort and the proportion of responders (on a weekly basis). The secondary outcomes are visual analog scale for IBS symptoms (on a daily basis), quality of life (at 0, 8, and 10 weeks), intestinal permeability, and composition of intestinal microbiota (at 0 and 8 weeks). The present study is designed to examine the safety and efficacy of GJS and Duolac7S combination therapy on D-IBS. Our study provides the clinical evidence of a new therapeutic strategy for D-IBS.