This section is from the book "A Treatise On Therapeutics, And Pharmacology Or Materia Medica Vol1", by George B. Wood. Also available from Amazon: Part 1 and Part 2.
Horsemint is the herb of Monarda punctata, an indigenous herbaceous plant, a foot or two high, growing preferably in light and gravelly soils, from New Jersey to the Gulf of Mexico. Its odour is aromatic, its taste warm, pungent, and bitterish. These properties depend on a volatile oil, which is obtained by distillation, is of a reddish-amber colour, an odour similar to that of the plant, and a hot, very pungent taste. Hot water will extract the virtues of the herb, but alcohol is a better solvent, Horsemint has the aromatic properties of the proper mints, but is more stimulating and less agreeable. It may be used as an antiemetic and carminative, and as a stimulant to the stomach in languid states of that organ; but is little employed in regular practice. An infusion may be made in the proportion of half an ounce to the pint, and given in wineglassful doses. Drank warm and freely, it will often induce perspiration, and has been thought to act as an emmenagogue; and, taken cold, it has been supposed t6 stimulate the kidneys. Hence it has been used in suppression of the menses, and of the urine.
The Volatile Oil (Oleum Monaruae. U.S.) is more used. It may be given as a stimulant and carminative in the dose of two or three drops, mixed with sugar and water; but it has attracted more attention as an active rubefacient. Applied to the skin, it causes redness, heat, and pain, and sometimes blisters. In cases not demanding a powerful and speedy impression, it should be diluted with olive oil before application.