Natural Products

Peppermint

Scientific names: Mentha x piperita. Peppermint is a hybrid of Mentha spicata (spearmint) and Mentha aquatica.

Common names: Peppermint also is known as menthol.

Efficacy-safety rating:

ÒÒ...Ethno or other evidence of efficacy.

Safety rating:

●...Little exposure or very minor concerns.

What is Peppermint?

This well-known perennial is a prototypical member of the mint family. Like all mints, it has a square purple-green stem with leaves of dark or light green, with purple and lilac-colored flowers. The plant generally is sterile and spreads by means of runners. A variety of types of peppermint exist, which are cultivated worldwide. Pharmaceutical oil is derived from 2 varieties, white (light-green leaves) and black (dark-green leaves) peppermint. This is not to be confused with Japanese peppermint oil, which is similar in odor but derived from a different species.

What is Peppermint used for?

Traditional and ethnobotanical uses

First described in England in 1696, peppermint and its oil have been used in Eastern and Western traditional medicine as an aromatic, antispasmodic, and antiseptic agent. It has been used in treating cancers, colds, cramps, indigestion, nausea, sore throat, and toothaches. Today, the oil is used widely as a flavoring in chewing gum, toothpastes, mouthwashes, cigarettes, and pharmaceuticals. It also is used as an ingredient in cough and cold preparations, and as a carminative for use in irritable bowel syndrome (IBS). As the menthol component, it is found in numerous antiseptic, antipruritic (anti-itch), and local anesthetic preparations.

GI effects

Human studies affirm peppermint oil's role in reducing symptoms of IBS. Peppermint oil has been shown to be more effective than placebo in reducing symptoms of dyspepsia in adults and children. Animal tests support the theoretical effect of peppermint oil in reducing nausea. However, studies in humans show that while menthol and peppermint oil are more effective than placebo, they are not more effective than standard treatments. Peppermint oil has been used traditionally in the management of gallstones with limited clinical information supporting this use. Peppermint oil exerts an antispasmodic action on smooth muscle, and has been found useful in patients with colonic and esophageal spasm.

Respiratory tract infections

Menthol is available in a variety of OTC products (eg, chest rubs, inhalations, lozenges, syrups) for the treatment of colds and related congestion and cough. Human studies have demonstrated antitussive and decongestant actions. In lozenges, the main action of menthol appears to be a subjective sensation of improved nasal airflow. Asthma patients used fewer bronchodilators and had fewer wheezing symptoms with the use of menthol.

Pain and sensory effects

In low concentrations, topical application of menthol causes a cooling sensation, while in higher concentrations, it causes local anesthesia and irritation. The irritant effect of menthol causes local vasodilation. This effect has been used to aid penetration of topical drugs. Menthol's sensory effects are utilized in commercial topical musculoskeletal products.

Other uses

Peppermint oil possessed antibacterial activity and weak antifungal properties in laboratory tests. The oil exhibits some CNS effects and reduces pain sensitivity in headaches. Peppermint oil aroma has shown an antisoporific (antisleep) effect and is being studied as aromatherapy for dementia.

What is the dosage of Peppermint?

Peppermint oil has been used as a carminative at doses of 0.1 to 0.24 mL. Up to 1,200 mg of the oil in enteric-coated tablets has been used to treat IBS.

Is Peppermint safe?

Contraindications

Do not administer peppermint oil to patients with gastroesophageal reflux or active gastric ulcers because the oil decreases esophageal sphincter pressure. Do not apply peppermint oil to the face, especially under the nose of a child or infant. Enteric-coated preparations are not recommended for use in children younger than 8 years of age.

Pregnancy/nursing

Documented adverse effects. Avoid use. Emmenagogue (to stimulate menstrual flow) effects.

Interactions

Peppermint oil may influence metabolism of certain drugs (including felodipine and simvastatin), increasing pharmacologic and adverse reactions. Absorption of caffeine may be delayed by menthol. Decreased cyclosporine levels have been reported with consumption of a tea containing 9 herbs, including peppermint.

Side Effects

Peppermint oil may cause allergic reactions characterized by contact dermatitis, flushing, and headache, and worsen the symptoms of hiatal hernias, heartburn, and stomach ulcers.

Toxicities

Peppermint generally is recognized as safe for human consumption as a seasoning or flavoring, although medicinal uses of the plant may cause adverse reactions (see Adverse Reactions).

References