||Peppermint Leaf/Peppermint Oil
Mentha x piperita (Botanical)
Menthae piperitae folium/Menthae piperitae
Peppermint is widely used for its antispasmodic, antiseptic, carminative,
anesthetic, and choleretic properties. It aids digestion and is held to be
helpful for many stomach problems, irritable bowel syndrome, nausea, morning
sickness, dysmenorrhea, diarrhea, constipation, and flatulence. In larger doses,
it may have an emmenagogic effect. Studies show that peppermint oil acts as a
choleretic, stimulating the flow of bile, which improves digestion. Peppermint
oil also has antiviral properties, inhibiting many viruses that cause digestive
Menthol, a major constituent of peppermint oil, is well known for its
external analgesic counter-irritant effects. It cools as well as numbs the skin,
producing effective relief from the itching caused by hives and poison ivy. A
combination of peppermint oil's analgesic and antispasmodic properties also make
it an effective remedy for headaches. Studies suggest that correct use of the
oil can be as effective as taking 1 g of acetaminophen.
Peppermint and menthol appear most frequently in cold medicines, where they
are effective as decongestants. The strong antiviral properties of peppermint
are most concentrated in the tea form, and drinking it will restrict the growth
of many cold and flu viruses. It is also very effective for a dry cough, because
it calms the throat muscles, and as an expectorant, because menthol thins the
Square stems grow up to two feet tall. Flowers are tiny, purple, in whorls
and terminal spikes, with four stamens. Leaves are opposite, simple, toothed,
and very fragrant. It blooms from July through August. Peppermint is native to
Europe and Asia; some types are indigenous to South Africa, South America, and
Australia. It is naturalized in North America and cultivated primarily in
Oregon, Washington, and Wisconsin.
The herb consists of the leaves and flowering tops of Mentha piperita
(family Lamiaceae) and is made up of volatile oil (0.5% to 4%) composed of
50% to 78% menthol and 5% to 20% menthol esterfied with various organic acids,
such as acetic and bovaleric. Also flavonoids (luteolin, menthoside), phenolic
acids, and triterpenes.
Packaged peppermint tea is widely available or may be made from dried fresh
Tinctures: Peppermint spirit is an alcoholic solution containing 10%
peppermint oil and 1% peppermint leaf extract. To make a tincture, add one part
peppermint oil to nine parts pure grain alcohol.
Enteric-coated capsules (0.2 ml of peppermint oil per capsule)
Creams or ointments (should contain 1% to 16% menthol): Mentholatum or Vicks
Traditional: antispasmodic, carminative, choleretic, antibacterial,
decongestant, external analgesic, antiemetic, aromatic, emmenagogue,
Conditions: irritable bowel syndrome, nausea, morning sickness, diarrhea,
dysmenorrhea, constipation, flatulence, gallstones, headache, hives, nasal
congestion, dry cough
Clinical applications: irritable colon, catarrhs of respiratory tract,
inflammation of oral mucosa, myalgic and neuralgic
Peppermint's primary active component is menthol, the focus of most
scientific experiments, which have determined it to be effective internally as
an antispasmodic, carminative, choleretic, decongestant, and antibacterial, and
externally as an analgesic.
Peppermint's carminative properties work by relaxing the esophageal
sphincter, allowing gas pressure to escape the stomach. Because of this,
peppermint should not be used in cases of gastroesophogeal reflux disease
because it may exacerbate the condition. A recent study reported that 89.5% of
patients with irritable bowel syndrome showed significant improvement in
abdominal symptoms after being treated with enteric-coated peppermint oil
capsules. The enteric coating allows the peppermint oil to reach the intestines
without being absorbed into the stomach. In the intestines, the oil is believed
to inhibit the hypercontractility of intestinal smooth muscle and restore proper
In vitro studies show that peppermint oil can inhibit and destroy influenza A
viruses, herpes simplex, mumps virus, Streptococcus pyogenes, Staphylococcus
aureus, Pseudomonas aeruginosa, and Candida albicans. The menthol and
related terpenes found in peppermint oil have been shown by several studies to
dissolve gallstones by lowering bile cholesterol levels while raising bile acid
and lecithin levels in the gallbladder.
Peppermint works as an external analgesic by blocking muscle contractions
caused by serotonin and substance P, but it also stimulates cold receptors on
the skin, which may influence the spinal cord's pain transmissions. The oil also
relaxes the pericranial muscles and increases blood flow to the capillaries,
making it an effective treatment for headaches.
|Dosage Ranges and Duration of
- For digestion and upset stomach, peppermint tea (infusion), 1 to 2
tsp. of dried leaves per 8 oz. of water, 3 to 4 cups daily between meals;
peppermint glycente for children, 1 to 2 ml daily
- For gallstones and irritable bowel syndrome, 1 to 2 enteric-coated
capsules tid between meals
- As an external analgesic, menthol in a cream or ointment form no more
than tid to qid
- For upset stomach or vomiting, 3 to 6 g of leaf, or 5 to 15 drops of
- For tension headaches, tincture of peppermint oil. Apply light
coating to entire forehead with fingertips or small sponge. If there is
occipital pain, apply to back of neck as well. Allow to
When taken as a tea, peppermint is usually considered safe, although
hypersensitivity reactions have been reported. Rare negative reactions to
enteric-coated peppermint oil capsules may include skin rash, heartburn,
bradycardia (slowed heartbeat), and muscle tremors. Menthol or peppermint oil
applied topically could cause contact dermatitis or rash. Peppermint oil should
be diluted and taken in small amounts, as excessive ingestion could cause
interstitial nephritis and acute renal failure. An estimated fatal dose of
menthol is 2 to 9 g if taken internally. There are no known mutagenic or
No contraindications to peppermint as an herb. Peppermint oil is
contraindicated by biliary tract obstruction, cholecystitis, and severe liver
damage. Infants and small children should not use peppermint tea or oil.
Pregnant or nursing mothers should use peppermint tea only in small doses and
those with a history of miscarriage should avoid it. Do not mistake oil for
In a study evaluating potential essential oils as transdermal delivery
agents, peppermint oil acted as a penetration enhancer for 5-fluorouracil (5-FU)
using excised rat skin (Abdullah et al. 1996). Peppermint oil enhanced the
permeation of 5-FU approximately 46-fold. The mechanism for the accelerated
percutaneous absorption of 5-FU combined with these essential oils may be due to
a combination of partition and diffusion.
|Regulatory and Compendial
On the U.S. FDA's list of herbs, peppermint is generally regarded as safe as
a dietary supplement. The German Commission E approves it for internal use as an
antispasmodic, carminative, choleretic, and decongestant, and for external use
as an analgesic.
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penetration of 5-fluorouracil through rat skin. Yao Hsueh Hsueh Pao.
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Duke J. The Green Pharmacy. Emmaus, Pa: Rodale Press; 1997.
Feng XZ. Effect of peppermint oil hot compresses in preventing abdominal
distension in postoperative gynecological patients [In Chinese]. Chung Hua Hu
Li Tsa Chih. 1997; 32:577-578.
Hills J. The mechanism of action of peppermint oil on gastrointestinal smooth
muscle. Gastroenterology. 1991;101:55-65.
Koch TR. Peppermint oil and irritable bowel syndrome. Am J Gastroenterol.
Kowalchik C, Hylton W, eds. Rodale's Illustrated Encyclopedia of
Herbs. Emmaus, Pa: Rodale Press; 1987.
Lawson MJ, Knight, RE, Tran K, Walker G, Robers-Thompson IC. Failure of
enteric-coated peppermint oil in the irritable bowel syndrome: a randomized
double-blind crossover study. J Gastroent Hepatol. 1988;3:235-238.
Mowrey D. The Scientific Validation of Herbal Medicine. New Canaan,
Conn: Keats Publishing, Inc; 1986.
Murray MT. The Healing Power of Herbs: The Enlightened Person's Guide to
the Wonders of Medicinal Plants. Rocklin, Calif: Prima Publishing; 1995.
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review and metaanalysis. Am J Gastroenterol. 1998;93:1131-1135.
Rees W. Treating irritable bowel syndrome with peppermint oil. Br Med J.
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Binghamton, NY: Pharmaceutical Products Press;
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