Oleum Monardae.—Oil of Horsemint.

Botanical name: 

Related entry: Monarda.—Horsemint

A volatile oil distilled from the fresh herb of Monarda punctata, Linné (Nat. Ord.—Labiatae).

Preparation and Description.—Oil of horsemint is obtained in this country from the fresh herb, by distillation with water. The yield is about 3 per cent. The oil is of a yellowish or brownish-amber color, having a penetrating, aromatic, thyme-like odor, like that of the plant, and a strong, pungent, somewhat acrid taste; and is soluble in alcohol. Its specific gravity is 0.930 to 0.940.

Chemical Composition.—Oil of horsemint contains thymol (monardin) and cymol, sometimes carvacrol, and traces of dextro-limonene. (For details, see Monarda.)

Action, Medical Uses, and Dosage.—Oil of horsemint is stimulant, antispasmodic, and antiemetic, and in the form of the essence, has been much used to allay nausea and vomiting in Asiatic cholera, cholera morbus, etc.; it relieves the diarrhoea of debility, its action in these cases being prompt and permanent. It stimulates the nervous system and increases cardiac force. It gives sleep and quiet when there is exhaustion with nervous excitation. It restores suppressed menses when due to colds, and given with turpentine or wintergreen it renders good service in the tympanites of enteric fever. Oil of horsemint serves well in the vomiting of inebriates, and in nausea accompanying a flatulent distension of the stomach. Externally, it is rubefacient and even vesicant, and has been advantageously used in low forms of fever, cholera infantum, paralysis, rheumatic and neuralgic pains, etc. It soon causes rubefaction when locally applied, affording in many instances almost immediate relief. The dose of the oil is from 2 to 5 drops on sugar; of the essence, from 10 to 30 drops in sweetened water.

King's American Dispensatory, 1898, was written by Harvey Wickes Felter, M.D., and John Uri Lloyd, Phr. M., Ph. D.