Peppermint is a hybrid mint plant. It is a cross between watermint and spearmint.1 Peppermint is native to Europe, but the herb has now grown widespread throughout the world.2 People everywhere value mint for it’s strong cooling scent, it’s cooling sensation on the skin, and it’s flavoring capabilities in baking, candy making, and drink preparation.

Peppermint has a long tradition of herbal use and is used by the Egyptians, Greeks, and the Europeans for medicinal purposes.3 Peppermint has been studied intensively for its use in the treatment of IBS and other intestinal disorders.4 Peppermint is known to have a high natural menthol content, contributing to its use throughout history to soothe sore throats. Menthol vapors that are produced from its oil can be inhaled to relax bronchial passages and relieve congestion.5

On the Importance of Menthol

Menthol is an organic compound that can be obtained from peppermint oil. Menthol has many known medicinal properties, including:

  • Pain relief – Menthol weakly activates the k-opioid receptors, which can be beneficial for pain relief.6 Different substances can activate the Kappa-opioid receptors in the brain. When the receptors are activated by these different substances (including menthol), they change both the perception of pain by the brain and reduce inflammatory pain nerve signaling pathways in the body, therefore, increasing the pain threshold.7
  • Muscle relaxant – Menthol’s mechanism of action as a muscle relaxant is by blocking voltage-sensitive sodium channels in the neuromuscular junction. This blockage reduces neural activity in the muscles, which in turn relaxes the muscles and reduces muscle spasms.8
  • Vasodilation – Menthol is a known vasodilator when it is applied to the skin. It increases blood flow to capillaries in the skin by dilating veins that are close to the dermis, or the top layer of the skin.9
  • Activating TRPM8 receptors – Menthol can chemically activate the TRPM8 receptors in the skin. These receptors are responsible for the cooling sensation that menthol is known for when menthol is inhaled, eaten, or applied topically to the skin.10 Activating the TRPM8 receptors has also been theorized to be a potential treatment protocol for eliminating prostate cancer.11 Finally, TRPM8 receptors that are activated in the intestinal tract correctly modulate inflammatory responses and can help to correct an overactive immune system in people suffering from inflammatory bowel diseases.12
  • Relieving congestion and pain from sore throats – Menthol has been used for centuries to help relieve bronchial/nasal congestion and sore throat pain by reducing inflammation and relaxing nasal, bronchial, and throat passageways.13

Uses of Peppermint Oil for Digestive Purposes

  • Peppermint oil has strong antibacterial properties.14 15
  • Relaxes the lower esophageal sphincter (LES), which can be beneficial in people suffering from achalasia. It can worsen heartburn symptoms in people with GERD by relaxing the LES. People with GERD (gastroesophageal reflux disease) should only use ECPO.16
  • Peppermint oil reduces spasms of the intestines.17
  • Peppermint oil can help relieve constipation.18
  • Peppermint oil may help relieve abdominal pain.19
  • Peppermint oil is used in the treatment of IBS (irritable bowel disease)20 and SIBO (small intestinal overgrowth syndrome).21
  • Topical peppermint oil cream can be used to help treat hemorrhoids.22

Enteric-Coated Peppermint Oil: Magic Bullet for Intestinal Issues?

Enteric-coated peppermint oil (ECPO) is extremely versatile in the treatment of intestinal issues. ECPO can be used in the treatment of intestinal infections, SIBO, IBS, chronic functional abdominal pain (CFAP), inflammatory bowel diseases, and hemorrhoids. It even helps in the relief of chronic constipation.

In a 2007 study, 75% of the patients in the study took enteric-coated peppermint oil for four weeks and had a major reduction in IBS symptoms. Some patients even went into remission during the study (compared to the 38% that took a placebo).23 Another study using ECPO was conducted in Iran in 2009 and produced similar treatment results. Results from the study concluded ECPO greatly reduced symptoms of IBS and can be theoretically used in the treatment of chronic functional abdominal pain.24

It has been theorized that ECPO is very effective in the treatment of both IBS and CFAP. The proposed mechanism of action is that the oil both reduces intestinal spasms25 and increases the pain threshold by activating k-opioid and TRPM8 receptors. Peppermint oil eliminates opportunistic bacteria in the colon and/or small intestine that have been linked to one of the possible causes of IBS26 27 and the main cause of SIBO.28

Supplementation of peppermint oil for a short period may produce loose stools and help relieve constipation. The mechanism of action for the loosening of stools may be that menthol is a mild irritant to the intestines and causes the intestines to draw in more water, causing it to act as an osmotic laxative to loosen stools. A reverse reaction may occur in people who have IBS-D—the peppermint oil may calm intestinal spams and regulate bowel movements so that their diarrhea is instead relieved.

Lastly, peppermint oil has even been used as an ingredient in a few natural hemorrhoid creams to help both treat and alleviate the pain caused by hemorrhoids. The peppermint oil in the cream acts as a vasodilator to the hemorrhoid tissue and helps increase blood flow to the afflicted area. Increasing blood flow to the tissue promotes healing by reducing swelling and the size of the hemorrhoid. The peppermint oil would also activate the k-opioid and TRPM8 receptors on the hemorrhoid tissue and would reduce pain.

When Should Peppermint Oil Not Be Used?

I do not recommend the use of peppermint oil in people with severe constipation or methane dominant archaea SIBO. Peppermint oil, especially enteric-coated peppermint oil can slow down the third wave of the MMC. The third wave of the MMC moves food into the duodenum from the stomach during digestion and propels food through the small intestine. Peppermint oil by interrupting the MMC can lead to further constipation and hinder recovery.29 30

I recommend Enteric coated peppermint oil spastic IBS (caused by vagal over-stimulation) or SIBO-D. It can also help with Chronic Functional Abdominal Pain not caused by SIBO as long as motility is functioning properly.

Recommended Forms of Peppermint Oil

Recommended forms of enteric-coated peppermint oil (known non-phthalate coating):

Other recommendation (possible phthalate coating):

Liquid peppermint oil (use very little, follow bottle instructions):

Peppermint oil hemorrhoid cream:

  1. http://bioweb.uwlax.edu/bio203/s2009/johnson_nic4/Classification.htm
  2. http://ag.arizona.edu/yavapai/publications/yavcobulletins/Growing%20Herbs.pdf
  3. http://www.greenmedinfo.com/blog/power-peppermint-15-health-benefits-revealed
  4. http://www.greenmedinfo.com/blog/power-peppermint-15-health-benefits-revealed
  5. http://umm.edu/health/medical/altmed/herb/peppermint
  6. http://www.ncbi.nlm.nih.gov/pubmed/11897159
  7. http://www.painresearchforum.org/news/8488-kappa-opioid-receptors-rekindling-flame
  8. http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=464364
  9. http://www.karger.com/Article/FullText/89139
  10. http://onlinelibrary.wiley.com/doi/10.1111/j.2042-7158.1994.tb03871.x/pdf
  11. http://cancerres.aacrjournals.org/content/64/22/8365
  12. http://www.findaphd.com/search/ProjectDetails.aspx?PJID=47927
  13. http://onlinelibrary.wiley.com/doi/10.1111/j.2042-7158.1994.tb03871.x/pdf
  14. http://www.sciencedirect.com/science/article/pii/S1878535211000232
  15. http://www.ncbi.nlm.nih.gov/pubmed/8893526
  16. http://www.aafp.org/afp/2007/0401/p1027.html
  17. http://www.med.nyu.edu/content?ChunkIID=21838
  18. http://www.patient.co.uk/medicine/peppermint-oil-capsules-colpermin-mintec-apercap
  19. http://umm.edu/health/medical/altmed/herb/peppermint
  20. http://umm.edu/health/medical/altmed/herb/peppermint
  21. http://www.altmedrev.com/publications/7/5/410.pdf
  22. http://www.alleviatehemorrhoids.com/9-miracles/
  23. http://www.sciencedirect.com/science/article/pii/S1590865807000618
  24. http://www.ncbi.nlm.nih.gov/pubmed/19507027
  25. http://www.med.nyu.edu/content?ChunkIID=21838
  26. http://www.sciencedaily.com/releases/2012/05/120525103354.htm
  27. http://www.ncbi.nlm.nih.gov/pubmed/17261128
  28. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3099351/
  29. http://www.ncbi.nlm.nih.gov/pubmed/10641042
  30. http://www.ncbi.nlm.nih.gov/pubmed/12601675