Botanical name

Peppermint - Mentha x piperita L.

Family

Labiatae (Lamiaceae)

Information about the plant

Peppermint probably emerged spontaneously towards the end of the 17th century from the cross between water mint (Mentha aquatica L.) and the Eurasian mint (Mentha spicata L. ssp. Spicata). Spearmint is in turn also a bastard variety. It is sterile and can only reproduce by vegetative propagation with its offshoots (stolons). From around 1750 peppermint was grown demonstrably in Mitcham, a suburb of London at the time. The generic name Mentha comes from the name of the nymph, Minthe, who according to a Greek legend turned into plant called "minthe" or "mintha" in ancient times. The peppery flavour of the leaves led to the designation of peppermint, Lat "piperita" (= peppered). Propagation work in terms of appearance, leaf colour, vigour, resistance characteristics, hardiness, oil content and oil composition have led to many subspecies, varieties and forms. A distinction can be made between the dark green ("black mint") varieties and bright green ("white mint") varieties. The stems and leaves of dark green varieties are reddish, the leaves are ovate; bright green species have lanceolate leaves. The still very significant "Mitcham" peppermint developed over 200 years ago in England is a dark green variety. The stems of the approx. 60cm tall plant are clearly angular, the leaves are decussate. By rubbing them they smell strongly of the essential oil they contain, peppermint oil. It is in glandular scales on the leaf surface. If these glands are broken open when rubbed they release the essential oil. The pale red flowers are in dense spikes.

Medicinally used parts of plants (herbal drug)

The leaves are used with their intense minty scent, which is clearly notable when rubbed - it comes from the essential oil contained in the leaves. The main farming areas are located in Thuringia, Bavaria, Spain and Bulgaria. Farms for the extraction of essential oil (peppermint oil) can be found in the United States, South America and Asia.

Constituents of the herbal drug

Peppermint leaves contain an essential oil ("peppermint oil"). It consists of 30 to 55% (-) menthol, and also contains 14-32% menthone, 2.8 to 10% menthyl acetate and other terpenes. (-)- Menthol is responsible for the characteristic scent. It also contains Lamiaceen tannins (main representatives: rosmarinic acid) and flavonoids.

Quality of the drug

The quality of the following drugs or drug preparations is specified in the European Pharmacopoeia (Ph. Eur.):

• Peppermint leaves (Mentha piperitae folium)
• Peppermint leaves dried extract (Menthae piperitae folii extractum siccum)
• Peppermint oil (Menthae piperitae aetheroleum)

Medical applications

Recognised medical use

Peppermint leaves
Internally for spasms and cramps in the stomach-intestinal tract and bile ducts, associated with flatulence (Commission E, ESCOP). The HMPC has classified peppermint leaves as a traditional herbal medicinal product (see "traditional use").

Peppermint oil
Internal use as described for the drug, the oil is applied externally in particular for irritable bowel syndrome and catarrh of the upper respiratory tracts, but also as an inhalant (Commission E, ESCOP).
Externally as a rub for myalgia (muscle pain) and neuralgia (nerve pain), particularly for tension headaches and skin symptoms such as itching, hives, painful skin irritation (ESCOP).
The HMPC has accepted peppermint oil for internal use as being effective against cramp pains in the gastrointestinal tract (especially irritable bowel syndrome), and for external use only the action against tension headaches for "well-established medicinal use"

Traditional use

Peppermint leaves
The HMPC has categorised peppermint leaves for the following applications as a traditional herbal medicine (§ 39a AMG). Based on many years of experience peppermint leaves can be used in mild cramp discomfort in the gastro-intestinal tract (bloating). Peppermint leaves are used in combination with other drugs for the digestive function or to release the mucus in the respiratory tract (traditionally in accordance with § 109a).

Peppermint oil
Peppermint oil has been classified by the HMPC for use externally in coughs and colds, with muscle pain and itchiness of intact skin as a traditional herbal medicinal product (§ 39a AMG) and internally it can be used as inhalant (see also "recognised medical use").

Herbal drug preparations in finished dosage forms

• Peppermint leaves as tea, even in teabags
• Fluid extract in drops and juice
• Alcoholic and aqueous extracts in drops
• Tincture as drops
• Dried extract in soluble instant teas
• Peppermint oil undiluted

Dosage

Prepared drugs: see package insert;
Tea infusion: drink 1 cup of warm freshly prepared mint tea three times a day. Tincture: 3 times daily, 2-3 ml peppermint oil: Take two drops on sugar or in water 1 to 2 times a day, daily dose is 3 to 6 drops. Externally: For an inhalation add 3 to 4 drops peppermint oil to hot water and inhale.
Adjust the dosage for children between 4 and 12 years old according to their body weight and their age.

Preparation of a tea

Pour 150ml of hot water over 1.5 g of chopped mint leaves (do not boil!). Let it stand for 5 to 10 minutes and then strain.

Notes

No internal use of peppermint oil with people that have gall stone disease, occlusion of bile ducts, gall bladder and liver damage. For external use do not apply peppermint oil directly onto mucous membranes or broken skin and never in the area around the eyes.
For infants and toddlers up to 2 years old, menthol can cause spasms or respiratory arrest, therefore peppermint oil may not be used in this age group. As a matter of precaution it is not recommended for children up to 4 years old.
There are no studies on the safety of using peppermint during pregnancy or lactation.

Side effects

When used externally there may be occasionally skin irritations and eczema, and internally stomach aches in people with sensitive stomachs. In the case of inhalation-sensitive patients may be show adverse respiratory reactions.

Interactions

None known.

References

Herbal drug monographs

HMPC, Commission E, ESCOP, WHO Vol. 2

Further literature

Wichtl: Teedrogen und Phytopharmaka, pg. 440
Schilcher: Leitfaden Phytotherapie, pg. 42
Van Wyk: Handbuch der Arzneipflanzen, pg. 201
Kommentar zum Europäischen Arzneibuch (Peppermint leaves, no. 0406; Peppermint oil, no. 0405; Peppermint leaves dried extract, no. 2382)