Peppermint's therapeutic uses

• DEFINITION: Natural plant product used to treat specific health conditions.
• PRINCIPAL PROPOSED USES: Dyspepsia, irritable bowel syndrome, other forms of spasms in the digestive tract
• OTHER PROPOSED USES:

• Inhaled: Nausea, respiratory congestion, colds, cough, mental health
• Topical: Breast-feeding support, tension headache, pain relief, skin conditions
• Oral: Gallstones, oral health

Overview

Peppermint is a relative of numerous wild mint plants. It was deliberately bred in the late seventeenth century in England to become the delightful-tasting plant so well known today. It is widely used in tea and as a flavoring or scent.

Peppermint tea also has a long history of medicinal use, primarily as a digestive aid and for the symptomatic treatment of cough, colds, and fever. Peppermint oil is used for chest congestion (Vicks VapoRub), as a local anesthetic (Solarcaine, Ben-Gay), and in the treatment of irritable bowel disease, also known as spastic colon. Several additional therapeutic uses for peppermint have been proposed. 

Therapeutic Dosages

The proper dosage of peppermint oil when treating irritable bowel syndrome is 0.2 to 0.4 milliliter (ml) three times a day of in enteric-coated capsule. The capsule has to be enteric-coated to prevent stomach distress. When used in herbal combinations to treat stomach problems, peppermint oil is taken at lower doses and is not enteric-coated.

Therapeutic Uses

Peppermint oil has shown promise for various conditions involving digestive issues. Most studies have involved irritable bowel syndrome (IBS), for which peppermint oil has shown considerable promise. Peppermint oil may also help reduce the pain caused by medical examinations of the colon and stomach and decrease the intestinal gas pain that frequently follows surgery. Peppermint oil may also be helpful for dyspepsia (a condition similar to IBS but involving the stomach instead of the intestines). Weak evidence, far too preliminary to rely upon, hints that peppermint oil might help dissolve gallstones.

Peppermint oil is also used in another way: as aromatherapy. This means it is inhaled, often by adding it to a humidifier. Weak evidence hints that inhaled peppermint oil might be helpful for relieving mucus congestion in the lungs and sinuses. One small study found benefits for chemotherapy patients who were given inhaled peppermint and saw a decrease in nausea and vomiting. Inhaling peppermint oil has also been suggested as a means of boosting mood and decreasing anxiety. However, further medical studies are necessary to confirm this use.

Scientific Evidence

Irritable bowel syndrome (IBS). Numerous studies have been conducted on peppermint oil for IBS. In one of the larger studies, 110 people with IBS were given either enteric-coated peppermint oil (187 milligrams, or mg) or a placebo three to four times daily, fifteen to thirty minutes before meals, for four weeks. The results showed significant improvements in abdominal pain, bloating, stool frequency, and flatulence. In a similar study, people who took peppermint oil capsules for eight weeks had less abdominal pain and discomfort than the placebo group.

In a study published in 2007, fifty-seven people with IBS symptoms were given either a placebo or peppermint oil. At the end of the study period, 75 percent of the patients in the peppermint oil group showed a marked reduction of IBS symptoms (defined, for this purpose, as a reduction of IBS symptom scores by more than 50 percent). In comparison, only 38 percent of the participants given a placebo showed an improvement of this magnitude, and this difference was statistically significant. In 2019, a study of 835 patients—the most comprehensive study to date—returned similar results, with the researchers concluding peppermint oil was an effective remedy for IBS symptoms.

Other forms of spasm in the digestive tract. A barium enema involves introducing a metal barium solution into the lower intestines. It commonly causes intestinal pain and spasms. A double-blind study of 141 individuals found that adding peppermint oil to the barium reduced the severity of intestinal spasms that occurred. Benefits were also seen in a large study conducted by different researchers. Another study found that peppermint oil reduced spasms in the stomach during a procedure called upper endoscopy. One study found that peppermint oil after C-section surgery reduced discomfort caused by intestinal gas.

Dyspepsia (minor indigestion). Peppermint oil is often combined with other essential oils to treat minor indigestion. For example, a double-blind, placebo-controlled study including thirty-nine individuals found that an enteric-coated peppermint-caraway oil combination taken three times daily for four weeks significantly reduced dyspepsia pain compared with placebo. Of the treatment group, 63.2 percent were pain-free after four weeks, compared with 25 percent of the placebo group.

Results from a double-blind, comparative study including 118 individuals suggest that the combination of peppermint and caraway oil is comparably effective to the no-longer-available drug cisapride. After four weeks, the herbal combination reduced dyspepsia pain by 69.7 percent, whereas the conventional treatment reduced pain by 70.2 percent.

In another double-blind study enrolling sixty individuals, a preparation of peppermint, caraway, fennel, and wormwood oils was compared with the drug metoclopramide. After seven days, 43.3 percent of the treatment group was pain-free, compared with 13.3 percent of the metoclopramide group. Metoclopramide reduces gastric emptying time (in other words, speeding the passage of food from the stomach into the intestines). Interestingly, some evidence suggests that peppermint oil may have the same effect.

Double-blind, placebo-controlled trials continue to be carried out on peppermint, although the majority investigated its efficacy for digestive issues rather than its additional therapeutic uses. Studies published in 2020, 2021, and 2024 all showed mixed results when peppermint was used for IBS. The organizers of all three of these studies concluded that while peppermint oil showed some benefit in reducing IBS symptoms, the placebo groups in the studies did as well. Larger-scale studies on peppermint are necessary to confirm its efficacy for treating any health conditions.

Safety Issues

At the standard dosage, enteric-coated peppermint oil is believed to be reasonably safe in healthy adults. However, case reports and one study in rats hint that peppermint might reduce male fertility. The species Mentha spicata may be more problematic in this regard than the more common M. piperita. Excessive doses of peppermint oil can be toxic, causing kidney failure and even death. A very high intake of peppermint oil can also cause nausea, loss of appetite, heart problems, loss of balance, and other nervous system problems. Safety in young children, pregnant or nursing women, and those with severe liver or kidney disease has not been established. In particular, peppermint can cause jaundice in newborn babies, so it should not be used for colic.

Use of peppermint oil may increase levels of the drug cyclosporine in the body. Persons taking cyclosporine who wish to take peppermint oil should notify their physician in advance so that their blood levels of cyclosporine can be monitored, and their dose can be adjusted if necessary. Conversely, those persons already taking both peppermint oil and cyclosporine should not stop taking the peppermint without informing their physicians. Ceasing to take peppermint may cause cyclosporine levels to fall.

Important Interactions

Those taking cyclosporine should not use peppermint oil (or stop using it) except in consultation with a physician.

Bibliography

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Efe Ertürk, Nuriye, and Sultan Taşcı. "The Effects of Peppermint Oil on Nausea, Vomiting and Retching in Cancer Patients Undergoing Chemotherapy: An Open Label Quasi-Randomized Controlled Pilot Study." Complementary Therapies in Medicine, vol. 56, 2021, p. 102587, doi.org/10.1016/j.ctim.2020.102587.

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Merat, S., et al. "The Effect of Enteric-Coated, Delayed-Release Peppermint Oil on Irritable Bowel Syndrome." Digestive Diseases and Sciences, vol. 55, no. 5, 2010, pp. 1385-1390.

"Peppermint Oil: Usefulness and Safety." National Center for Complementary and Integrative Health, Oct. 2020, www.nccih.nih.gov/health/peppermint-oil. Accessed 11 Oct. 2024.

Sayyah, Melli M., et al. "Effect of Peppermint Water on Prevention of Nipple Cracks in Lactating Primiparous Women." International Breastfeeding Journal, vol. 2, 2007, p. 7.

Weerts, Zsa Zsa R. M., et al. "Efficacy and Safety of Peppermint Oil in a Randomized, Double-Blind Trial of Patients With Irritable Bowel Syndrome." Gastroenterology, vol. 158, no. 1, 2020, pp. 123-136, doi.org/10.1053/j.gastro.2019.08.026. Accessed 11 Oct. 2024.