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Effect of fibre, antispasmodics, and peppermint oil in the treatment of irritable bowel syndrome: systematic review and meta-analysis

BMJ 2008; 337 doi: (Published 14 November 2008) Cite this as: BMJ 2008;337:a2313

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  1. Alexander C Ford, clinical fellow1,
  2. Nicholas J Talley, professor of medicine2,
  3. Brennan M R Spiegel, assistant professor of medicine3,
  4. Amy E Foxx-Orenstein, associate professor of medicine4,
  5. Lawrence Schiller, clinical professor5,
  6. Eamonn M M Quigley, professor of medicine and human physiology6,
  7. Paul Moayyedi, professor of gastroenterology1
  1. 1Gastroenterology Division, McMaster University, Health Sciences Centre, 1200 Main Street West, Hamilton, ON, L8N 3Z5, Canada
  2. 2Department of Medicine, Mayo Clinic Florida, Jacksonville, FL, USA
  3. 3VA Greater Los Angeles Healthcare System; UCLA/VA Center for Outcomes Research and Education, Los Angeles, CA, USA
  4. 4Division of Gastroenterology and Hepatology, Mayo Clinic Rochester, MN, USA
  5. 5Digestive Health Associates of Texas, Baylor University Medical Center, Dallas, TX, USA
  6. 6Department of Medicine, Cork University Hospital, Ireland
  1. Correspondence to: A C Ford alexf12399{at}
  • Accepted 24 September 2008


Objective To determine the effect of fibre, antispasmodics, and peppermint oil in the treatment of irritable bowel syndrome.

Design Systematic review and meta-analysis of randomised controlled trials.

Data sources Medline, Embase, and the Cochrane controlled trials register up to April 2008.

Review methods Randomised controlled trials comparing fibre, antispasmodics, and peppermint oil with placebo or no treatment in adults with irritable bowel syndrome were eligible for inclusion. The minimum duration of therapy considered was one week, and studies had to report either a global assessment of cure or improvement in symptoms, or cure of or improvement in abdominal pain, after treatment. A random effects model was used to pool data on symptoms, and the effect of therapy compared with placebo or no treatment was reported as the relative risk (95% confidence interval) of symptoms persisting.

Results 12 studies compared fibre with placebo or no treatment in 591 patients (relative risk of persistent symptoms 0.87, 95% confidence interval 0.76 to 1.00). This effect was limited to ispaghula (0.78, 0.63 to 0.96). Twenty two trials compared antispasmodics with placebo in 1778 patients (0.68, 0.57 to 0.81). Various antispasmodics were studied, but otilonium (four trials, 435 patients, relative risk of persistent symptoms 0.55, 0.31 to 0.97) and hyoscine (three trials, 426 patients, 0.63, 0.51 to 0.78) showed consistent evidence of efficacy. Four trials compared peppermint oil with placebo in 392 patients (0.43, 0.32 to 0.59).

Conclusion Fibre, antispasmodics, and peppermint oil were all more effective than placebo in the treatment of irritable bowel syndrome.


  • This study was done to inform the American College of Gastroenterology monograph on irritable bowel syndrome. We thank William Chey, Lawrence Brandt, Phillip Schoenfeld, and Edgar Achkar for their contributions to the discussion concerning the role of fibre, antispasmodics, and peppermint oil in the treatment of irritable bowel syndrome; and Premysl Bercik, Peter Bytzer, and Heidi Krall for assisting us with the translation of foreign language articles.

  • Contributors: All authors conceived and designed the study and drafted the manuscript and critically revised it for important intellectual content. ACF and PM acquired, analysed, and interpreted the data. ACF is guarantor.

  • Funding: This study was funded by the American College of Gastroenterology. The authors’ work was independent of the funders.

  • Competing interests: NJT has received consultancy fees from Procter and Gamble, Lexicon Genetics, Astellas Pharma US, Pharma Frontiers, Callisto Pharmaceuticals, AstraZeneca, Addex Pharma, Ferring Pharma, Salix, MGI Pharma, McNeil Consumer, Microbia, Dynogen, Conexus, Novartis, and Metabolic Pharmaceuticals, and has received research support from Novartis, Takeda, GlaxoSmithKline, Dynogen, and Tioga. EMMQ has received consultant’s and speaker’s bureau fees from Nycomed, Boehringer Ingelheim, Procter and Gamble, Reckitt Benckiser, and Prometheus, and holds equity in Alimentary Health. PM holds a chair at McMaster University partly funded by an unrestricted donation by AstraZeneca, and has received consultant’s and speaker’s bureau fees from AstraZeneca, AxCan Pharma, Nycomed, and Johnson and Johnson.

  • Ethical approval: Not required.

  • Provenance and peer review: Not commissioned; externally peer reviewed.

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