Herbal Combination Shows Benefit for Irritable Bowel Syndrome

Reviewed: Madisch A, Holtmann G, Plein K, Hotz J. Treatment of irritable bowel syndrome with herbal preparations: results of a double blind, randomized, placebo-controlled, multi-centre trial. Aliment Pharmacol Ther. 2004;19(3):271-279.

Irritable bowel syndrome (IBS) is one of the most common gastrointestinal disorders. About 10 to 20% of adolescent and adult Westerners experience symptoms consistent with IBS.[ 1] The disorder is characterized by abdominal pain or discomfort for at least 12 weeks, which is relieved by defecation. It is associated with a change in stool frequency (constipation) and/or stool consistency (diarrhea). The pathophysiology of IBS is not well understood. There is no cure and treatment is targeted at symptom relief. Available treatments are helpful in a small proportion of patients. Herbal medicines have been used in many countries, but controlled data are lacking.

The objective of this study was to evaluate the efficacy and safety of the commercially available herbal preparation STW 5 (sold under the name Iberogast™, Steigerwald Arzneimittelwerk GmbH, Darmstadt, Germany; distributed in the United States by Enzymatic Therapy, Green Bay, WI [independent health food stores] and PhytoPharmica, Green Bay, WI [pharmacies and healthcare professionals]). STW 5 contains bitter candytuft plant, (a.k.a. clown's mustard; Iberis amara L., Brassicaceae), German chamomile flower (Matricaria recutita L., Asteraceae), peppermint leaves (Mentha x piperita L., Lamiaceae), caraway fruit (Carum carvi L., Apiaceae), licorice root (Glycyrrhiza glabra L., Fabaceae), lemon balm leaves (Melissa officinalis L., Lamiaceae), celandine herb (i.e., aerial parts of Chelidonium majus L., Papaveraceae), angelica root and rhizome (Angelica archangelica L., Apiaceae), and milk thistle fruit (Silybum marianum [L.] Gaertn. Asteraceae).

Men and women (n = 203) with persistent IBS participated in this randomized, placebo-controlled, double-blind, multi-center study based in Germany. The patients discontinued taking their current medications prescribed for IBS one week prior to randomization. The patients were assigned to 1 of 4 treatment groups: ( 1) STW 5; ( 2) a special research preparation called STW 5-II containing bitter candytuft, German chamomile flower, peppermint leaves, caraway fruit, licorice root, and lemon balm leaves; (3) bitter candytuft monoextract (BCT); and (4) a placebo.

The trial medications were taken 3 times daily (20 drops) for 4 weeks. The quantity of each component and the manufacturer were not mentioned in the article. (Editor's Note: Manufacturer's information on contents was obtained online.) Symptoms were evaluated.

There were no significant demographic or baseline differences between groups; however, the groups were not: sub-divided by the type of IBS from which they suffered. According to the ROME II criterion,[ 1] there are 3 sub-types of IBS: constipation predominant (IBS-C), diarrhea predominant (IBS-D), and alternating (IBS-Mixed). There was no indication as to how many of each subtype were included in each of the 4 treatment groups. Given the fact that the mechanisms of action may be different for IBS-C and IBS-D, this is a critical factor that was overlooked in this study. Compared to placebo, treatment with STW 5 and STW 5-II significantly improved abdominal pain (P < 0.01) and IBS symptoms (flatulence, sensation of tension or fullness, sensation of incomplete evacuation, constipation, diarrhea) (P ? 0.001). Treatment with BCT did not significantly differ from placebo. Physicians judged the efficacy to be "very good" or "good" in 65% of the patients treated with STW 5 and 73% of the patients treated with STW 5-II. STW 5 and STW 5-II had "very good" or "good" tolerability. There were no serious adverse events and only 2 minor adverse events were noted: one in the BCT group (headache, therapy was continued) and one in the STW 5 group (constipation, therapy was continued).

Pharmaceuticals used to treat IBS are effective for either diarrhea-predominant or constipation predominant IBS, but not for both. STW 5 and 5-II appear to be effective regardless of the predominance of the symptoms, but again, this is difficult to interpret given the lark of stratification of assignment of groups by predominant symptomatology. The effect of STW 5 and 5-II may be mediated via an influence on gastrointestinal motility. Clinical trials of patients with IBS have a high placebo response (40-70%) in short-term trials. Despite this high placebo response, STW 5 and 5-II performed remarkably well compared to placebo. The authors conclude that STW 5 and 5-II are highly effective for the treatment of patients with IBS. Considering the excellent study design and statistics, the results of this study appear convincing.

This is not the first time a multi-ingredient herbal combination has been found safe and effective for treating symptoms of IBS. Previously, a Chinese herbal formulation has been shown to be effective in treating patients with IBS.[ 2] In this study, both a fixed formulation of Chinese herbs and variant herbal formulations customized for each patient based on traditional Chinese medicine diagnosis were both shown to be effective, thereby giving credence that various multi-herb preparations can be used safely and effectively to treat IBS.

PHOTO (COLOR): Celandine Chelidonium majus

References
1. Drossman DA, ed. Rome II: The Functional Gastrointestinal Disorders. 2nd ed. McLean, VA: Degnon Associates, Inc.; 2000.

2. Bensoussan A, Talley NJ, Hing M, Menzies R, Guo A, Ngu M. Treatment of irritable bowel syndrome with Chinese herbal medicine. JAMA. 1998;280(18):1585-1589.

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By Heather S. Oliff, PhD and Mark Blumenthal

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