Peppermint oil

Also called enteric-coated peppermint, peppermint capsules.

Dr Chad OkayFounder, Suna Health

3 min read. Updated .

Enteric-coated peppermint oil capsules are one of the better-evidenced over-the-counter treatments for IBS pain and bloating. The active compound, menthol, relaxes smooth muscle in the gut. Meta-analyses find peppermint oil beats placebo for global symptoms, with a number needed to treat of about 3 to 4. Standard dose is 0.2 ml three times a day, before meals, in enteric-coated capsules.

How it works

Menthol blocks calcium channels in the smooth muscle of the gut, producing antispasmodic effects. It relaxes the muscle wall, easing the cramping and bloating sensation that defines IBS for many sufferers. Enteric coating prevents the capsule from breaking down in the stomach (where it would cause heartburn) and delivers the oil to the small intestine and colon.

Evidence

  • BSG IBS guidance recommends peppermint oil as first-line antispasmodic.
  • Meta-analyses (Khanna 2014, J Clin Gastroenterol; Alammar 2019, BMC Complement Altern Med; Ingrosso 2022, Aliment Pharmacol Ther, note: no Cochrane review exists) show peppermint oil better than placebo for global IBS symptoms, with NNT around 3 to 4 for global symptoms (NNT for abdominal pain ranges higher, up to 7).
  • Effect strongest for pain and bloating; less impact on stool form.
  • Onset usually within 1 to 2 weeks; can be continued for longer if symptoms persist.
  • Safe for use up to 12 weeks in trials; longer-term safety not extensively studied but appears benign.

Dosing

  1. The licensed UK dose (Colpermin SmPC) is 0.2 ml in an enteric-coated capsule, up to three times a day, before meals. A pharmacist can confirm what suits you.
  2. Brands in UK: Colpermin, Mintec, IBgard.
  3. Take whole. Crushing or chewing destroys the enteric coating and causes heartburn.
  4. Trial for 4 weeks. If no improvement, stop.
  5. Combine with dietary changes (low-FODMAP if appropriate) for best effect.

Side effects and who should not take it

  • Heartburn (more common if you have GORD or hiatus hernia; people with existing heartburn may find it worsens).
  • Anal burning sensation in a small minority.
  • Allergic reactions (rare).
  • Avoid in pregnancy and breastfeeding (limited safety data).
  • Not recommended in children (the UK Colpermin SmPC states no experience under age 15).
  • Do not use peppermint tea as a substitute, it does not deliver the same dose to the small intestine.

Before self-treating

Peppermint oil is for a gut pattern that has been recognised for what it is, not for papering over one that has never been looked at. A changed bowel habit that has not settled deserves checking at any age (the FIT test has no minimum duration), and bleeding, weight going down on its own, unexplained anaemia, or a strong family history of bowel cancer each need a doctor first. New patterns after 50 deserve a look before being labelled IBS, and if capsules reliably worsen heartburn, a pharmacist can suggest alternatives.

Common questions

Does peppermint tea work for IBS?
Mildly, for some people. Tea has far less menthol than enteric-coated capsules and is not delivered to the lower gut. It can soothe nausea and aid mild post-meal discomfort. For real IBS symptom control, the capsules are what trials have studied.
Can I take it long-term?
Up to 12 weeks is well-studied. Longer-term safety appears reasonable but is less rigorously documented. Many people take it during flares only and stop in between.
Will it help reflux?
Often makes reflux worse, not better. Menthol can trigger heartburn symptoms, so it is risky if you have reflux (though recent manometry studies question whether it actually relaxes the lower oesophageal sphincter). If you have both IBS and GORD, peppermint oil is risky and you should ask a clinician.
What about peppermint oil for bloating without IBS?
Anecdotal. Most evidence is in people with diagnosed IBS. For occasional non-IBS bloating, simpler interventions (walking after meals, smaller portions, lower evening sodium) are better first steps.

Sources

Written by Dr Chad Okay. Contributor: Dr Parisah Hussain, MBChB, BSc (Hons), DRCOG, MRCGP. Last updated 17 September 2026. From Digests.

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