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Open Source Apothecary At Home / Digestion
One of the few herbs whose mechanism is known, whose trials exist, and whose effect is modest.
remedyPeppermint's active principle is menthol, which activates the cold receptor TRPM8 and relaxes smooth muscle by blocking calcium entry. That is a plausible mechanism for a gut that is cramping, and unlike most herbal claims the trials actually exist.
The honest shape of the evidence is this: peppermint oil beats placebo for IBS symptoms in pooled analysis, the effect is real, and the certainty of the evidence is low. One meta-analysis concluded the oil "was superior to placebo for the treatment of IBS, but adverse events were more frequent, and quality of evidence was very low" — that sentence contains both the finding and its limit, and both belong on the label. The adverse events are mostly heartburn and reflux, because relaxing the lower oesophageal sphincter is the same mechanism that relaxes the gut.
Enteric-coated capsules are the point. Menthol relaxes the sphincter at the top of the stomach as readily as the muscle further down, which is why plain peppermint oil causes heartburn. The trials that work best used capsules designed to release in the intestine. A cup of peppermint tea has a far lower dose and does not have the same trial evidence, though it is a reasonable and harmless thing to drink after a meal.
Peppermint tea for indigestion has better support than its reputation suggests, and it is the preparation a household can actually make. One caveat that catches people out: peppermint relaxes the lower oesophageal sphincter, so for someone with reflux it can make heartburn worse even as it settles the stomach.
Menthacarin was shown to be effective and safe for the treatment of FD and represents a promising option for symptoms of IBS.PubMed 36502789 ↗
Peppermint oil was superior to placebo for the treatment of IBS, but adverse events were more frequent, and quality of evidence was very low.PubMed 35942669 ↗
Future studies should assess the long-term efficacy and safety of peppermint oil and its efficacy relative to other IBS treatments including antidepressants and antispasmodic drugs.PubMed 24100754 ↗
Evidence-based therapy in IBS provides a number of effective treatment options beyond the fact that many novel compounds under development have failed to reach the market.PubMed 21389791 ↗
The role of peppermint oil in the symptomatic treatment of IBS has so far not been established beyond reasonable doubt.PubMed 9672344 ↗
Based on moderate to very low-certainty evidence, we identified some herbal medicines that may be effective in improving symptoms of dyspepsia.PubMed 37323050 ↗
Peppermint tea
Peppermint oil capsules
Fresh or dried leaf. Dried leaf is more consistent for tea. Fresh leaf is pleasant in summer but its menthol content varies and it wilts fast.