Peppermint oil may help ease bloating and other symptoms in some people with irritable bowel syndrome (IBS), according to a couple of clinical trials. The evidence is strongest for enteric-coated capsules rather than tea or essential oils, and it does not show that peppermint oil works for every kind of bloating.
Why might peppermint oil affect bloating at all?
Peppermint oil contains menthol, which is thought to relax the smooth muscle of the gut. In theory, that could calm the cramping and spasms that often come with IBS and make the abdomen feel tight and swollen. This is why it has been studied in IBS rather than in bloating on its own.
It helps to be clear about what bloating is. It is a feeling of fullness or pressure, sometimes with visible distension. It can come from trapped gas, slow transit, food intolerances, hormonal shifts across the menstrual cycle, or a sensitive gut that over-reacts to normal amounts of gas. Peppermint oil is only relevant to some of these causes.
What does the research actually show?
Two of the trials we looked at tested peppermint oil capsules against a placebo in adults with IBS.
An Italian trial in carefully selected patients
In a double-blind, placebo-controlled study from Italy, 57 people with IBS took enteric-coated peppermint oil capsules (two capsules, twice a day) or a placebo for four weeks. The researchers had first excluded small intestinal bacterial overgrowth, lactose intolerance and coeliac disease, because these conditions can mimic IBS and may have muddied the results of earlier studies. Participants scored symptoms including abdominal bloating, pain, diarrhoea, constipation and urgency. They were assessed before treatment, at four weeks, and again four weeks after stopping (Cappello et al., 2007).
A US trial using a sustained-release capsule
A second four-week, double-blind trial tested a sustained-release peppermint oil formulation, taken three times daily, in 72 adults with IBS-M (mixed) or IBS-D (diarrhoea-predominant). Their average age was about 41 and 75% were women. At four weeks, the peppermint oil group had a 40% reduction in their Total IBS Symptom Score, compared with 24.3% in the placebo group, a statistically significant difference (Cash et al., 2016).
Two points of caution. First, that figure refers to the overall IBS symptom score, not bloating alone. Second, one of the authors is affiliated with the company behind the formulation, and the trial was small and short. A fair reading is that the results are encouraging but not definitive.
Does this apply to everyone who feels bloated?
No. Both studies recruited people who met diagnostic criteria for IBS. If your bloating comes from something else, such as constipation, a food intolerance, a large heavy meal or hormonal changes before your period, there is no good evidence from these trials that peppermint oil will help.
It is also worth noting that the studies used capsules. We have no data here on peppermint tea, peppermint sweets or essential oil. A cup of peppermint tea can be a pleasant, soothing ritual after a meal, but it should not be assumed to have the same effect as a formulated capsule.
If you are not sure what is behind your symptoms, our guide to digestive bloating and IBS explains the common patterns, and why you can feel bloated after healthy meals covers the everyday triggers many women overlook, from raw salads to fizzy water.
What should you know before trying it?
- Get symptoms checked first. Persistent bloating can occasionally be linked to conditions such as coeliac disease, ovarian problems or other gut disorders. See your GP if bloating is new, constant or worsening, or if it comes with weight loss you cannot explain, blood in the stool, persistent pain, vomiting, fever or night-time symptoms.
- Enteric coating matters. Both trials used capsules designed to release the oil further along the gut. Oil released too early in the stomach may cause heartburn or reflux in some people.
- Side effects are possible. Heartburn, a burning sensation when passing stools and mouth or throat irritation are among those reported with peppermint oil in general. If you have reflux or a hiatus hernia, ask first.
- Check with a professional. If you take regular medication, are pregnant or breastfeeding, or are considering it for a child, speak to your GP or pharmacist. In Malta, your local pharmacist is a good first stop for product questions.
- Do not use it as a substitute for a diagnosis. It is a supplement, not a medicine for any condition, and supplements are not intended to diagnose, treat or prevent disease.
What else can help with bloating day to day?
Whatever you decide about peppermint oil, the basics make a difference for many women.
- Keep a food and symptom diary for two to three weeks to spot patterns.
- Eat more slowly and chew well. Talking while eating and gulping drinks can mean swallowing more air.
- Stay hydrated, especially through Malta’s hot summers, when dehydration can slow digestion.
- Move after meals. A gentle walk in the evening cool is often better than lying on the sofa.
- Build up fibre gradually rather than all at once, as a sudden jump can increase gas.
If you suspect particular carbohydrates are the trigger, a structured approach may help. Our explainer on the low FODMAP diet describes how it works and why it is best done with professional guidance.
Frequently asked questions
How long does peppermint oil take to work for bloating?
The trials ran for four weeks, and symptom scores were measured at the end of that period. The second trial also reported an early reduction at 24 hours, but individual responses vary and some people notice nothing at all.
Is peppermint tea as good as peppermint oil capsules?
We do not know. The studies discussed here used capsules, so they cannot tell us whether tea has a similar effect. Tea is generally a gentle option, but it can aggravate reflux in some people.
Can I take peppermint oil if I have reflux?
Peppermint can relax the muscle at the top of the stomach and may make heartburn worse for some people. Speak to your GP or pharmacist before trying it.
When is bloating a reason to see a doctor?
Book an appointment if bloating is persistent, getting worse, or comes with pain, changes in bowel habits, blood in the stool, unexplained weight loss or loss of appetite. Do not wait for a supplement to make a difference.
References
- Peppermint oil (Mintoil) in irritable bowel syndrome: a double-blind placebo-controlled trial (2007)
- A novel delivery system of peppermint oil and IBS symptoms (2016)
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