Peppermint

Information
Application
Notes
References

Photo: Sertürner Bildarchiv

Botanical name

Mentha x piperita L.

Family

Lamiaceae

Common name

Peppermint, English Mint, Brandy Mint

Information about the plant

Peppermint probably originated spontaneously toward the end of the 17th century from the cross between water mint (Mentha aquatica L.) and spearmint (Mentha spicata L. ssp. spicata). Spearmint is itself a hybrid. Peppermint is sterile and can reproduce only by vegetative propagation through its offshoots (stolons).

From around 1750, peppermint was cultivated in Mitcham, then a suburb of London. The genus name Mentha derives from the name of the nymph, Minthe, who, according to Greek legend, turned into a plant called "minthe" or "mintha". The peppery flavor of the leaves led to the designation of peppermint, from Latin piperita (= peppered).

Selective breeding focused on appearance, leaf color, vigor, resistance characteristics, hardiness, oil content, and oil composition has led to numerous subspecies, varieties and forms. A distinction can be made between the dark green ("black mint") and bright green ("white mint") varieties.

The stems and leaves of dark green varieties are reddish. The leaves are ovate, whereas the bright green species have lanceolate leaves. The still highly valuated "Mitcham" peppermint, developed over 200 years ago in England, is a dark green variety. The stem of the approximately 60 cm tall plant is distinctly square, with leaves arranged in oppositely. When rubbed, they release the strong aroma of the essential oil (peppermint oil) contained in glandular scales on the leaf surface. When these glands are broken, the essential oil is released. The pale red flowers are densely arranged in spikes.

Medicinally used parts of plants (herbal drug)

The leaves (peppermint leaves - Menthae piperitae folium) are used for their intense minty aroma, which is clearly noticeable when rubbed. This scent is caused by the essential oil, which has a high menthol content.

The main cultivation areas are in Thuringia and Bavaria (Germany), as well as in Spain and Bulgaria. Crops 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 essential oil (‘peppermint oil’), lamiaceae tannins (mainly rosmarinic acid), and flavonoids. Peppermint oil consists of 30 to 55% (-)-menthol, 14 to 32% menthone, 2.8 to 10% menthyl acetate, and other terpenes. (-)-Menthol is responsible for the characteristic aroma of the oil.

Quality of the drug

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

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

The quality of peppermint tincture (Menthae piperitae tincture) is specified in the German Drug Codex (DAC).

Medical applications

Recognised medical use

Peppermint leaves
The HMPC has classified peppermint leaves as a traditional herbal medicinal product (see ‘Traditional use’).
ESCOP: Digestive complaints, flatulence, and gastritis (stomach catarrh). These indications are based on long-standing use in humans.

Peppermint oil
The HMPC has recognized the use of peppermint oil in the form of gastro-resistant coated tablets for internal treatment of cramp-like complaints in the gastrointestinal tract (especially irritable bowel syndrome) as ‘well-established use’. This also applies to the external use of the oil in liquid or semi-solid form for tension headaches (see also ‘Traditional use’).
ESCOP: Internal use for the symptomatic treatment of digestive complaints such as flatulence, irritable bowel syndrome, coughs, and colds. External use for colds, rheumatic complaints, tension headaches, and skin symptoms such as itching, hives, and painful skin irritations.

Traditional use

The HMPC has classified peppermint leaves as a traditional herbal medicine (Article 16a of Directive 2001/83/EC). Based upon long-standing use, peppermint leaves can be used in the form of tea, as a powder in tablets, or as a tincture for mild cramp-like digestive complaints and flatulence.

Based upon long-standing use, the HMPC has also classified peppermint oil in liquid or solid form, for internal and external use against coughs and colds as a traditional herbal medicinal product (Article 16a of Directive 2001/83/EC). This also applies to the external use of the oil for local muscle pain and itching when the skin is not damaged. Peppermint oil can also be used internally as an inhalant and externally as a mouthwash. See also ‘Recognized medical use’.

Herbal drug preparations in finished dosage forms

Peppermint leaves for tea, also 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 in gastro-resistant medicinal forms

Dosage

Finished medicinal product: See patient information leaflet.

Tea: Drink one cup of warm, freshly prepared peppermint tea three times a day. Tincture: Three times daily, 2-3 ml.

Peppermint oil: Take 2 drops on sugar or in water one to two times a day, daily dose is 3 to 6 drops.

Externally: For inhalation, add 3 to 4 drops of peppermint oil to hot water and inhale.

Adjust the dosage for children between 4 and 12 years old according to their body weight and age.

Preparation of a tea

Pour 150ml of hot water (do not boil!) over 1.5 g of chopped peppermint leaves. Let steep for 5 to 10 minutes, then strain.

Notes

No internal use of peppermint oil with people with gallstones, bile duct obstruction, or gallbladder 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 of age, menthol can cause spasms or respiratory arrest; therefore, peppermint oil must not be used in this age group. As a precaution, it is not recommended for children under 4 years of age.

There are no studies on the safety of peppermint use during pregnancy or lactation.

Peppermint oil contains pulegone and menthofuran, which have been shown to be carcinogenic in high doses in animal studies. However, as these two substances are only present in low concentrations in the oil, there is no risk when peppermint oil is used as directed.

Side effects

External use may occasionally cause skin irritation and eczema, while internal use may cause gastric problems in individuals with sensitive stomachs. Sensitive patients may experience adverse respiratory reactions when inhaling the product.