Clinical studies have shown that peppermint leaves stimulate bile production and reduce the tendency for bloating and gas in the intestin. Peppermint oil is antibacterial, and the menthol it contains can also have an analgesic and cooling effect. Its effectiveness, however, is weak, which is why natural remedies contain higher levels of essential oils. The most important active ingredients in peppermint are the essential oils, rosmarinic acid, and flavonoids.
From Wikipedia: “Peppermint (Mentha × piperita, also known as Mentha balsamea Willd.) is a hybrid mint, a cross between watermint and spearmint. Indigenous to Europe and the Middle East, the plant is now widespread in cultivation in many regions of the world. It is occasionally found in the wild with its parent species.”
“In 2014, world production of peppermint was 92,296 tonnes, led by Morocco with 92% of the world total reported by FAOSTAT of the United Nations. Argentina accounted for 8% of the world total.
In the United States, Oregon and Washington produce most of the country's peppermint, the leaves of which are processed for the essential oil to produce flavorings mainly for chewing gum and toothpaste.”
Culinary and other uses:
“Fresh or dried peppermint leaves are often used alone or with other herbs in herbal teas (tisanes, infusions). Peppermint is used for flavouring ice cream, candy, fruit preserves, alcoholic beverages, chewing gum, toothpaste, and some shampoos, soaps and skin care products.
Menthol activates cold-sensitive TRPM8 receptors in the skin and mucosal tissues, and is the primary source of the cooling sensation that follows the topical application of peppermint oil.”
“Peppermint oil is also used in construction and plumbing to test for the tightness of pipes and disclose leaks by its odor.”
“Peppermint oil has a high concentration of natural pesticides, mainly pulegone (found mainly in Mentha arvensis var. piperascens cornmint, field mint, Japanese mint, and to a lesser extent (6,530 ppm) in Mentha × piperita subsp. nothosubsp. piperita) and menthone. It is known to repel some pest insects, including mosquitos, and has uses in organic gardening.
The chemical composition of the essential oil from peppermint (Mentha x piperita L.) was analyzed by GC/FID and GC-MS. The main constituents were menthol (40.7%) and menthone (23.4%). Further components were (+/-)-menthyl acetate, 1,8-cineole, limonene, beta-pinene and beta-caryophyllene.”
Research and health effects:
“Peppermint oil is under preliminary research for its potential as a short-term treatment for irritable bowel syndrome and has been used in traditional medicine for a limited number of minor ailments that remain scientifically unconfirmed for effectiveness. Peppermint oil may also act as a carminative, cholagogue, antibacterial, and secretolytic, and it has a cooling action. Externally, peppermint oil has been used for muscle pain, nerve pain and relief from itching.
High doses of peppermint oil (500 mg) can cause mucosal irritation and mimic episodes of heartburn. Usage of peppermint is thought to relax the lower esophageal sphincter, thus causing acid reflux, but a study disproved this theory, making peppermint safe to use as a flavoring in antacid medication.
The aroma of peppermint has been studied for possible memory- and alertness-enhancing properties.”
“The toxicity studies of the plant have received controversial results. Some authors reported that the plant may induce liver disease, while others found that it protects against liver damage caused by heavy metals. Toxicities of the plant may vary among cultivars and are dose dependent, an effect possibly related to pulegone.
With the limitation that the concentration of pulegone should not exceed 1%, it has been concluded that Mentha × piperita (peppermint) oil, Mentha × piperita (peppermint) extract, Mentha × piperita (peppermint) leaves, Mentha × piperita (peppermint) water are safe as used in cosmetic formulations.
When peppermint oil products are taken with antacid, they dissolve quickly and may cause heartburn and nausea. Due to the menthol constituent, topical use of peppermint oil around the facial or chest areas of infants and young children, especially around the nose, can induce apnea, laryngeal and bronchial spasm, acute respiratory distress with cyanosis, or respiratory arrest.”