Peppermint oil, enteric-coated
Coated peppermint oil capsules ranked first among the treatments compared for overall irritable bowel symptoms. The certainty is low, but the cost and risk are small.
At a glance
| Our verdict | Worth trying for irritable bowel once warning signs are excluded. |
| Best use | Irritable bowel |
| How sure the evidence is | Low |
| Cost a month | About $15 to $25 |
Written for adults in Canada. It explains the evidence; it is not advice for you personally. Last reviewed 20 October 2026.
Supplement Check
Is it right for you?
Bowel symptoms are not always irritable bowel. Your check asks about the warning signs first, then about reflux and your medicines, before suggesting peppermint oil. Our Supplement Check looks at:
- Any warning sign that needs a doctor first
- Reflux (gastro-oesophageal reflux disease) or a hiatus hernia
- No stomach acid (achlorhydria)
- Gallstones
- Pregnancy
- Every medicine you take
Coming soon. The Supplement Check and the Online Health Assessment open once our safety testing is complete.
$59 when it opens, paid once. Adults 18 and over, anywhere in Canada. While the service is new, Dr. French reads every report himself, and your report arrives within 3 working days. More about the Supplement Check
What it is
Peppermint oil, rich in L-menthol, in capsules with an enteric (delayed-release) coating, so the oil is released in the bowel rather than the stomach. Choose an enteric-coated product with a Canadian licence (NPN).
How it acts
Menthol relaxes the smooth muscle of the bowel wall by blocking calcium channels, which may ease cramping. It also acts on a cold-sensing receptor on gut nerves (TRPM8), which may dull gut pain. This is mechanism; the trials are the evidence.
What it is used for, and what the evidence says
For irritable bowel syndrome (IBS), once the warning signs have been ruled out: weight loss, bleeding from the bowel, anaemia, a new change in bowel habit after 50, symptoms that wake you at night, or a family history of bowel cancer or coeliac disease. Those go to a doctor, not to a supplement.
| Use | What the trials found | How sure we are |
|---|---|---|
| Irritable bowel: overall symptoms and pain | In a network analysis comparing soluble fibre, antispasmodics and gut–brain medicines, peppermint oil left 37% fewer people without improvement than placebo (relative risk 0.63) and ranked first for overall symptoms. [1] Certainty is low: few trials at low risk of bias, lasting 4 to 12 weeks. | Low |
| Use beyond 12 weeks | The trials lasted 4 to 12 weeks. Our review found no longer-term trials. | No evidence (no trial) |
How sure we are: High means further research is very unlikely to change the answer; Moderate, it might; Low, it may well change; Very low, we are very unsure. These follow the GRADE method that guideline panels use.
Benefits
- Overall irritable bowel symptoms and pain: more people improve than on placebo (relative risk of no improvement 0.63), low certainty. [1]
- Cheap and available without a prescription.
Risks and side effects
- Heartburn and reflux, more so if the coating dissolves early.
- Burning around the back passage.
Interactions with medicines
In the test tube, peppermint oil weakly blocks one of the liver enzymes that clear medicines (CYP3A4); our review found no evidence that this matters in people, but we are cautious with medicines whose levels must be exact. The main interaction is with acid-lowering medicines, which dissolve the coating too early.
| Medicine | What can happen | What to do |
|---|---|---|
| Antacids, H2 blockers, proton-pump inhibitors (acid-lowering medicines) | The coating dissolves early in the stomach: more heartburn and reflux | Discuss with your doctor; usually avoid together |
| Ciclosporin | Possible higher levels (weak CYP3A4 blocking in the test tube) | Discuss with your doctor |
Who should not take it
- Any warning sign: weight loss, bleeding from the bowel, anaemia, a new change in bowel habit after 50, symptoms that wake you at night, or a family history of bowel cancer or coeliac disease. See a doctor first.
- Reflux (gastro-oesophageal reflux disease) or a hiatus hernia.
- No stomach acid (achlorhydria).
- Gallstones.
- Pregnancy: limited data.
- Under 18: outside the Supplement Check.
Dose and timing
- 180 to 225 mg, 2 or 3 times a day, 30 to 60 minutes before meals.
- Swallow the capsule whole. Chewing or opening it defeats the coating.
- Enteric-coated product only, with an NPN.
- How to tell it is working: score your symptoms (an IBS symptom score or a symptom diary) before you start and at 4 weeks. If nothing has changed, stop.
What we know about Canadians
No Canadian data on irritable bowel syndrome or on peppermint oil use in our review.
How sure are we: not graded. Our Canadian population review did not cover irritable bowel.
An honest comparison: irritable bowel symptoms
Warning signs first: they go to a doctor, not to this table. Cost a month in Canadian dollars.
| Option | Effect | How sure we are | Cost a month (CAD) |
|---|---|---|---|
| Peppermint oil, enteric-coated | 37% fewer people left without improvement (relative risk 0.63); ranked first for overall symptoms [1] | Low | $15 to $25 |
| Probiotics | Some strains may help; uncertain across almost all analyses [4] | Low to Very low | $30 to $60 |
| Soluble fibre, built up slowly (the trials used psyllium; we use barley beta-glucan first, oat beta-glucan if you avoid gluten, and psyllium only with published heavy-metal results) | 17% fewer people still had symptoms (relative risk 0.83): 1 in 7 helped; bran did not help [2] | Moderate | $10 to $15 |
| Low FODMAP diet with a dietitian, then foods brought back | Ranked first for pain, bloating and bowel habit; unblinded, specialist settings [3] | Low | Dietitian $30 to $60 |
| Gut-directed psychological therapy (CBT, hypnotherapy) | Effective in trials (not pooled in our review) | Moderate | $0 to $200 |
| Low-dose amitriptyline, 10 to 30 mg at night | 27 points lower on the IBS symptom severity score than placebo at 6 months [5]; tricyclics ranked first for pain [1] | High | $8 to $10 |
Read honestly: soluble fibre has the best-graded evidence and costs least. Peppermint oil ranked first for overall symptoms, but on low-certainty evidence. Low-dose amitriptyline, a prescription medicine, has the strongest trial of all.
Our verdict
Recommended for adults with an irritable bowel pattern once the warning signs are excluded, alongside soluble fibre: an enteric-coated capsule, 180 to 225 mg two or three times a day before meals, for 4 weeks. If symptoms have not changed by then, stop.
Not for anyone with reflux, a hiatus hernia, gallstones, or on acid-lowering medicine, and not during pregnancy.
It ranked first for overall symptoms among the treatments compared, it costs $15 to $25 a month, and its side effects are mild and stop when it stops. The certainty is low, so we say so, and we pair it with soluble fibre, which has better-graded evidence. A 4-week trial tells each person whether it works for them.
Supplement Check
Before you buy it, get it checked
Bowel symptoms are not always irritable bowel. Your check asks about the warning signs first, then about reflux and your medicines, before suggesting peppermint oil. Our Supplement Check looks at:
- Any warning sign that needs a doctor first
- Reflux (gastro-oesophageal reflux disease) or a hiatus hernia
- No stomach acid (achlorhydria)
- Gallstones
- Pregnancy
- Every medicine you take
Coming soon. The Supplement Check and the Online Health Assessment open once our safety testing is complete.
$59 when it opens, paid once. Adults 18 and over, anywhere in Canada. While the service is new, Dr. French reads every report himself, and your report arrives within 3 working days. More about the Supplement Check
Disclosure of financial interest
White Pine Medical earns money from products bought through our Fullscript dispensary. Dr. French's Code of Ethics requires him to tell you this. You do not have to buy anything from us: every product is named by its ingredient and dose so you can buy it at any pharmacy, and the advice is the same wherever you buy it, or if you buy nothing.
References
- Black CJ, Yuan Y, Selinger CP, Camilleri M, Quigley EMM, Moayyedi P, et al. Efficacy of soluble fibre, antispasmodic drugs, and gut-brain neuromodulators in irritable bowel syndrome: a systematic review and network meta-analysis. Lancet Gastroenterol Hepatol. 2020;5(2):117-31.
- Moayyedi P, Quigley EM, Lacy BE, Lembo AJ, Saito YA, Schiller LR, et al. The effect of fiber supplementation on irritable bowel syndrome: a systematic review and meta-analysis. Am J Gastroenterol. 2014;109(9):1367-74.
- Black CJ, Staudacher HM, Ford AC. Efficacy of a low FODMAP diet in irritable bowel syndrome: systematic review and network meta-analysis. Gut. 2022;71(6):1117-26.
- Goodoory VC, Khasawneh M, Black CJ, Quigley EMM, Moayyedi P, Ford AC. Efficacy of probiotics in irritable bowel syndrome: systematic review and meta-analysis. Gastroenterology. 2023;165(5):1206-18.
- Ford AC, Wright-Hughes A, Alderson SL, Ow PL, Ridd MJ, Foy R, et al. Amitriptyline at low-dose and titrated for irritable bowel syndrome as second-line treatment in primary care (ATLANTIS): a randomised, double-blind, placebo-controlled, phase 3 trial. Lancet. 2023;402(10414):1773-85.
Costs marked as estimates are typical Canadian retail or pharmacy prices, before any drug plan. Certainty grades are ours unless the review gave its own.