Enteric-coated peppermint-oil capsules in the treatment of irritable bowel syndrome: A prospective, randomized trial


To determine the efficacy and tolerability of an enteric-coated peppermint-oil formulation (Colpermin), we conducted a prospective, randomized, double-blind, placebo-controlled clinical study in 110 outpatients (66 men/44 women; 18–70 years of age) with symptoms of irritable bowel syndrome. Patients took one capsule (Colpermin or placebo) three to four times daily, 15–30 min before meals, for 1 month. Fifty-two patients on Colpermin and 49 on placebo completed the study. Forty-one patients on Colpermin (79%) experienced an alleviation of the severity of abdominal pain (29 were pain-free); 43 (83%) had less abdominal distension, 43 (83%) had reduced stool frequency, 38 (73%) had fewer borborygmi, and 41 (79%) less flatulence. Corresponding figures for the placebo group were: 21 patients (43%) with reduced pain (4 were pain-free) 14 (29%) with reduced distension, 16 (32%) with reduced stool frequency, 15 (31%) with fewer borborygmi, and 11 (22%) with less flatulence. Symptom improvements after Colpermin were significantly better than after placebo (P<0.05; Mann-Whitney U-test). One patient on Colpermin experienced heartburn (because of chewing the capsules) and one developed a mild transient skin rash. There were no significant changes in liver function test results. Thus, in this trial, Colpermin was effective and well tolerated.

This is a preview of subscription content, access via your institution.


  1. 1.

    Talley NJ, Zinsmeister AR, Van Dyke C, et al. Epidemiology of colonic symptoms and the irritable bowel syndrome. Gastroenterology 1991;101:927–934.

    PubMed  CAS  Google Scholar 

  2. 2.

    Schlemper RJ, Van DJ, Vandenbroucke JP, et al. Peptic ulcer, non-ulcer dyspepsia and irritable bowel syndrome in the Netherlands and Japan. Scand J Gastroenterol 1993;28(Suppl 200):33–41.

    Article  Google Scholar 

  3. 3.

    Drossmann DA. Irritable bowel syndrome. Gastroenterologist 1994;2:315–326.

    Google Scholar 

  4. 4.

    Lind CD. Motility disorders in the irritable bowel syndrome. Gastroenterol Clin North Am 1991;20:279–295.

    PubMed  CAS  Google Scholar 

  5. 5.

    Fukuda S, Muranaka M, Nomura T, Satake M. Brain-gut interactions in irritable bowel syndrome: Physiological and psychological aspects. Nippon Rinsho Jpn J Clin Med 1992;50:2703–2711.

    Google Scholar 

  6. 6.

    Collins SM. Is the irritable gut an inflamed gut? Scand J Gastroenterol Suppl 1992;192:102–105.

    PubMed  Article  CAS  Google Scholar 

  7. 7.

    Hills JM, Aaronson PI. The mechanism of action of peppermint oil on gastrointestinal smooth muscle. Gastroenterology 1991; 101:55–65.

    PubMed  CAS  Google Scholar 

  8. 8.

    Rees WDW, Evans BK, Rhodes J. Treating irritable bowel syndrome with peppermint oil. BMJ 1979;2:835–837.

    PubMed  CAS  Article  Google Scholar 

  9. 9.

    Dew MJ, Evans BK, Rhodes J. Peppermint oil for the irritable bowel syndrome: A multicentre trial. Br J Clin Pract 1984;38:394–398.

    PubMed  CAS  Google Scholar 

  10. 10.

    Schneider MME, Otten MH. Efficacy of Colpermin in the treatment of patients with irritable bowel syndrome (abstract). Gastroenterology 1990;98(5):A389.

    Google Scholar 

  11. 11.

    Somerville KW, Richmond CR, Bell GD. Delayed-release peppermint oil capsules (Colpermin) for the spastic colon syndrome: A pharmacokinetic study. Br J Clin Pharmacol 1984;18:638–640.

    PubMed  CAS  Google Scholar 

Download references

Author information



Corresponding author

Correspondence to Gran-Hum Chen.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Liu, JH., Chen, GH., Yeh, HZ. et al. Enteric-coated peppermint-oil capsules in the treatment of irritable bowel syndrome: A prospective, randomized trial. J Gastroenterol 32, 765 (1997). https://doi.org/10.1007/BF02936952

Download citation

Key words

  • Colpermin
  • irritable bowel syndrome
  • peppermint oil