Peppermint

Botanical name: Mentha piperita

Parts used and where grown

Peppermint is a hybrid of water mint and spearmint and was first cultivated near London in 1750. Peppermint is now cultivated widely, particularly in the U.S. and Europe. The two main cultivated forms are the black mint, which has violet-coloured leaves and stems and a relatively high oil content, and the white mint, which has pure green leaves and a milder taste. The leaves are used medicinally.

Peppermint has been used in connection with the following conditions (refer to the individual health concern for complete information):

Rating	Health Concerns
	Irritable bowel syndrome (combination with caraway oil)
	Gingivitis (periodontal disease) Indigestion Irritable bowel syndrome Shingles (postherpetic neuralgia) (topical) Tension headache (topical)
	Chronic candidiasis Colic Common cold Gallstones Low back pain (topical) Poison ivy and poison oak dermatitis
Reliable and relatively consistent scientific data showing a substantial health benefit. Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit. For an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support and/or minimal health benefit.

Historical or traditional use (may or may not be supported by scientific studies)

Recognized in the early 18th century, the historical use of peppermint is not dramatically different than its use in modern herbal medicine. Classified as a carminative herb, peppermint has been used as a general digestive aid and employed in the treatment of indigestion and intestinal colic by herbalists.¹

Active constituents

Peppermint leaves yield approximately 0.1–1.0% volatile oil which is composed primarily of menthol (29–48%) and menthone (20–31%).² Peppermint oil is classified as a carminative (prevents and relieves intestinal wind).³ It may also relieve spasms in the intestinal tract. Peppermint oil or peppermint tea is often used to treat wind and indigestion.

Three double-blind trials found that enteric-coated peppermint oil reduced the pain associated with intestinal spasms, commonly experienced in irritable bowel syndrome (IBS).⁴ ⁵ ⁶ However, another trial found no effect of peppermint on IBS.⁷ A double-blind trial found that an enteric-coated combination of peppermint and caraway oils was superior to a placebo for people with gastro-intestinal complaints including IBS.⁸ A combination of peppermint, caraway seeds, and two other carminative herbs (fennel seeds and wormwood) was reported to be effective for gastro-intestinal complaints including IBS in another double-blind study.⁹

A tea of peppermint is a traditional therapy for colic in babies but has never been investigated in a human trial. Peppermint should be used cautiously in babies (see side effects below).

Peppermint oil’s relaxing action also extends to topical use. When applied topically, it acts as an analgesic and reduces pain.¹⁰ A trial of topical peppermint oil applied to the temples of healthy volunteers (with or without eucalyptus oil) found that peppermint oil had a muscle-relaxing action and it decreased tension.¹¹ Topical peppermint oil alone reduced pain in people with tension headaches as well.

How much is usually taken?

For internal use, a tea can be made by pouring 1 cup (250 ml ) of boiling water over 1 heaped teaspoon (5 grams) of the dried leaves and steeping for five to ten minutes. Three to four cups (750–1000 ml) daily between meals can be taken to relieve stomach and gastro-intestinal complaints.¹² Peppermint leaf tablets and capsules, 3–6 grams per day, can be taken. For treatment of irritable bowel syndrome, 1–2 enteric-coated capsules containing 0.2 ml of peppermint oil taken two to three times per day is recommended.

For headaches, a combination of peppermint oil and eucalyptus oil diluted with base oil can be applied to the temples at the onset of the headache and every hour after that or until symptom relief is noted.

Are there any side effects or interactions?

Peppermint tea is generally considered safe for regular consumption. Peppermint oil can cause burning and gastro-intestinal upset in some people.¹³ It should be avoided by people with chronic heartburn, severe liver damage, inflammation of the gallbladder, or obstruction of bile ducts.¹⁴ People with gallstones should consult a physician before using peppermint leaf or peppermint oil. Some people using enteric-coated peppermint capsules may experience a burning sensation in the rectum. Rare allergic reactions have been reported with topical use of peppermint oil. Peppermint oil should not be applied to the face—in particular, the nose—of children and babies. Peppermint tea should be used with caution in babies and young children, as they may choke in reaction to the strong menthol. Chamomile is usually a better choice for this group for treating colic and mild gastro-intestinal complaints.

At the time of writing, there were no well-known drug interactions with peppermint.

References

1. Foster S. Herbs for Your Health. Loveland, CO: Interweave Press, 1996, 72–3.

2. Bradley PR (ed). British Herbal Compendium, vol 1. Bournemouth, Dorset UK: British Herbal Medicine Association, 1992, 174–6.

3. Tyler VE. Herbs of Choice: The Therapeutic Use of Phytomedicinals. Binghamton, NY: Pharmaceutical Products Press, 1994, 56–7.

4. Dew MJ, Evans BK, Rhodes J. Peppermint oil for the irritable bowel syndrome: a multicenter trial. Br J Clin Pract 1984;38:394–8.

5. Liu J-H, Chen G-H, Yeh H-Z, et al. Enteric-coated peppermint-oil capsules in the treatment of irritable bowel syndrome: a prospective, randomized trial. J Gastroenterol 1997;32:765–8.

6. Rees W, Evans B, Rhodes J. Treating irritable bowel syndrome with peppermint oil. Br Med J 1979; 2:835–6.

7. Nash P, Gould SR, Barnardo DB. Peppermint oil does not relieve the pain of irritable bowel syndrome. Br J Clin Pract 1986;40:292–3.

8. May B, Kuntz HD, Kieser M, Kohler S. Efficacy of a fixed peppermint/caraway oil combination in non-ulcer dyspepsia. Arzneimittelforschung 1996;46:1149–53.

9. Westphal J, Hörning M, Leonhardt K. Phytotherapy in functional abdominal complaints: Results of a clinical study with a preparation of several plants. Phytomedicine 1996;2:285–91.

10. Göbel H, Schmidt G, Dwoshak M, et al. Essential plant oils and headache mechanisms. Phytomedicine 1995;2:93–102.

11. Göbel H, Schmidt G, Soyka DS. Effect of peppermint and eucalyptus oil preparations on neurophysiological and experimental algesimetric headache parameters. Cephalalgia 1994;14:228–34.

12. Wichtl M. Herbal Drugs and Phytopharmaceuticals. Boca Raton, FL: CRC Press, 1994, 336–8.

13. Sigmund DJ, McNally EF. The action of a carminative on the lower esophageal sphincter. Gastroent 1969;56:13–8.

14. Blumenthal M, Busse WR, Goldberg A, et al. (eds). The Complete Commission E Monographs: Therapeutic Guide to Herbal Medicines. Boston, MA: Integrative Medicine Communications, 1998, 180–2.

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The information presented in Healthnotes is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or chemist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires September 2008.