Traditional herbal medicines may improve symptoms of abdominal pain, disturbed bowel movements, and/or bloating and distension caused by Irritable Bowel Syndrome (IBS). This was the conclusion of a systematic review of clinical studies that is published in the latest update of The Cochrane Library.

Authors searched for studies that evaluated the effectiveness of traditional herbs including Chinese, Tibetan and Indian herbal medicines and found 75 different randomised trials. The trials varied in quality, and investigated a wide range of different preparations. Most of the trials had been conducted in China and published in Chinese.

"Many of the trials were small, so it is premature to recommend herbal medicines for routine use in IBS, but there is evidence that some of the medicines did improve the global symptoms of IBS," says lead Review Author Prof Jianping Liu, who works both at the Evidence-based Chinese Medicine Centre for Clinical Research and Evaluation at Beijing University of Chinese Medicine, and at the National Research Centre in Complementary and Alternative Medicine (NAFKAM), University of Tromso, Norway.

Medicines that showed promise included Chinese herbal formulation and individualised herbal formulation; STW 5; SW 5_ii; as well as Tibetan herbal formula Padma Lax. The Chinese herbal medicine Tongxie Yaofang showed a statistically significant effect on global symptoms, as did the Indian Ayurvedic formula of two herbs.

Six small trials reported that combining conventional and herbal medicines produced greater benefits than using conventional therapies alone, but the Authors believe that larger trials are needed to confirm this finding.

"There is a great need for further rigorously conducted trials that look to see whether it is possible to replicate these positive effects," says Prof Liu.

One of the problems with comparing the results of different trials is the wide range of formulas used, and the imprecision with which different medicines are prepared. "For these trials to be useful they must also improve the description of the herbal medicines being tested," adds Prof Liu.

1. Review Paper: Liu JP, Yang M, Liu YX, Wei ML, Grimsgaard S. Herbal medicines for treatment of irritable bowel syndrome. The Cochrane Database of Systematic Reviews 2006, Issue 1. Art. No.: CD004116.pub2. DOI: 10.1002/14651858.CD004116.pub2.

2. The Cochrane Library contains high quality health care information, including Systematic Reviews from The Cochrane Collaboration. These Reviews bring together research on the effects of health care and are considered the gold standard for determining the relative effectiveness of different interventions. The Cochrane Collaboration (cochrane) is a UK registered international charity and the world's leading producer of systematic Reviews. It has been demonstrated that Cochrane Systematic Reviews are of comparable or better quality and are updated more often than the Reviews published in print journalsª.

3. The Cochrane Library can be accessed at thecochranelibrary. Guest users may access abstracts for all Reviews in the database, and members of the media may request full access to the contents of the Library. For further information, see contact details below.

4. A number of countries have national provisions by which some or all of their residents are able to access The Cochrane Library for free. These include:

-- Australia nicsl.au/Cochrane
--New Zealand moht.nz/cochranelibrary or nzgg.nz or cochrane.nz
--Denmark vifab.dk or sundhedsportalen.dk or deff.dk or cochrane.dk
--England nelh.nhs/cochrane.asp
--Finland terveysportti.fi
--Ireland All residents within the Island of Ireland can access The Cochrane Library for free, thanks to funding for a national provision by The Health Research Board in Dublin and The Research and Development Office in Belfast.
--Norway cochrane.no
--Scotland nes.scot.nhs
--Spain update-software/Clibplus/ClibPlus.asp
--South Africa sahealthinfo/evidence/databases.htm
--Sweden sbu.se
--Wales All residents of Wales with access to the Internet can access The Cochrane Library for free, thanks to funding provided by The Welsh Assembly Government.
--The Canadian Province of Saskatchewan thecochranelibrary
--The US State of Wyoming thecochranelibrary

5. There are also several programmes, such as the Health InterNetwork Access to Research Initiative (HINARI) that provide access in developing countries. To find out whether your country is included in any of these programmes/provisions, or to learn how to get access if you don't already have it, please visit: thecochranelibrary.

If you would like to see a full list of Reviews published in the new issue of The Cochrane Library, or would like to request full access to the contents of The Library, please contact.

ª Jadad AR, Cook DJ, Jones A, Klassen TP, Tugwell P, Moher M, et al. Methodology and reports of systematic Reviews and meta-analysies: a comparison of Cochrane Reviews with articles published in paper-based journal.

John Wiley & Sons, Inc.
www.interscience.wiley