This section is from the book "Materia Medica Pharmacy, Pharmacology And Therapeutics", by W. Hale White. Also available from Amazon: Materia Medica Pharmacy, Pharmacology And Therapeutics..
The leaves and tops of Mentha piperita Smith (nat. ord. Labiata.
Wild in Asia, Europe, and North America; cultivated.
Leaves about 5 cm. long, petiolate, ovate-lanceolate, acute, sharply serrate, glandular, nearly smooth, the few hairs containing crystals of Menthol in one or more thin cells; branches quadrangular, often purplish; flowers in terminal, conical spikes, with a tubular, five-toothed, often purplish, calyx, a purplish, four-lobed corolla, and four short stamens; odor aromatic; taste pungent and cooling.
Its chief constituents are - (1) A volatile oil, (see below); (2) A liquid, and (3) a crystalline Menthol.
Spirit of Peppermint is contained in Mistura Rhei et Sodae.
Dose, 5 to 15 m.; .30 to 1.00 c.c.
A volatile oil distilled from Peppermint.
A colorless, or yellowish, or greenish-yellow liquid, becoming darker and thicker by age and exposure to the air, having the characteristic, strong odor of Peppermint, and a strongly aromatic, pungent taste, followed by a sensation of cold when air is drawn into the mouth. Sp. gr., 0.900 to 0.920.
The chief constituents are - (1) Menthene, C10H18, the liquid Terpene obtained by distillation. (2) Menthol, the solid Stearopten (q. v.), 50 to 65 per cent.
Oil of Peppermint is contained in Pilulae Rhei Compositae.
Dose, 1 to 5 m.; .06 to .30 c.c.
Dose, 1/2 to 2 fl. oz.; 15. to 60. c.c.
2. Spiritus Menthae Piperitae. - See above.
The action of oil of peppermint is the same as that of volatile oils generally, but the cool, numb feeling often produced by volatile oils after the sensation has passed off is especially well marked with oil of peppermint; and this effect, which is due to the menthol in it, has caused it to be applied externally in neuralgia. Like many other volatile oils it is a powerful antiseptic. It is in common use as the " peppermint test" for defective plumbing.
It is often used as a powerful stomachic and carminative, and also as a flavoring agent.