This section is from the book "A Treatise On Therapeutics, And Pharmacology Or Materia Medica Vol2", by George B. Wood. Also available from Amazon: Part 1 and Part 2.
As directed in the U. S. Pharmacopoeia, juniper consists of the fruit of Juniperus communis, or common juniper, a well-known evergreen shrub, indigenous in Europe, but introduced into this country, where it grows wild in many places. In addition to the fruit, which is the only part generally used, the Edinburgh and Dublin Colleges for. merly directed also the tops, which have similar properties. Though the berries are sometimes collected in this country, they are inferior to those brought from the South of Europe.
Properties and Active Principle. The berries are globular, about as large as a pea, often covered with a glaucous bloom, but of a shining blackish-purple colour when that has been removed, as it often is by rubbing. Their odour is aromatic; their taste sweetish, warm, slightly bitterish, and terebinthinate. Their virtues are extracted by boiling water and alcohol. Besides a considerable proportion of saccharine matter, they contain a peculiar volatile oil, upon which their virtues chiefly if not exclusively depend, and which is obtained separate by distillation with water.
Juniper is gently stimulant, cordial to the stomach, carminative, and diuretic. The last-mentioned effect is produced by the direct action of the volatile oil, which is absorbed, and, escaping somewhat altered through the kidneys, gives to the urine a violet odour. The stimulant operation upon the urinary organs is so considerable, when the medicine is taken freely, as sometimes to occasion symptoms approaching to strangury. Occasionally the diuretic action is very decided, and I have known edematous effusion to be entirely removed by this medicine unaided; but it is generally used only as an adjuvant to other diuretics. in this capacity, it often answers an excellent purpose in dropsy, especially in connection with the saline diuretics, the sedative effect of which upon the digestive function it tends to counteract by its stomachic properties, while it furthers their action on the kidneys.
Juniper has been used, with a view to its stimulant operation on the urinary passages, in chronic affections of these parts, connected with mucous or muco-purulent discharge; as chronic pyelitis, catarrh of the bladder, gleet, and leucorrhoea. it has also been employed as an alterative in scorbutic and eruptive disorders, as a gentle stimulant in debility of the stomach and bowels, and as an emmenagogue in atonic conditions of the uterus. But little reliance can be placed upon it in any of these affections. Almost the only use at present made of it is as an adjuvant to diuretics, and especially as a vehicle for bitartrate of potassa, for which it is very much and advantageously employed in this country.
The bruised berries have sometimes been given in substance, rubbed up with sugar, in the dose of a drachm or two, three or four times a day; but the common form of administration is that of infusion (infusum Juniperi, U. S.). An ounce of the bruised fruit should be macerated for an hour in a pint of boiling water, and the whole given in wineglassful doses during the twenty-four hours. The berries were an ingredient of the compound decoction of broom of the late London Pharmacopoeia. (See Broom.) The tops, or soft terminal branches of the shrub, have similar properties with the fruit, though less agreeable. They may be used in the same way.
Oil of Juniper (Oleum Juniperi, U. S,, Br.) is officinal, and considerably used. it is lighter than water, colourless or yellowish, with a terebinthinate or balsamic odour and taste, and of difficult solubility in alcohol. in the dose of from five to fifteen drops, three times a day, which may be increased if necessary, it may be used as an adjuvant and corrective of other diuretics, especially digitalis, nitre, and cream of tartar, when not forbidden by any excess of general excitement, or by local irritation in the alimentary canal or urinary organs.
The British Pharmacopoeia has a Simple Spirit, and the U. S. a Compound Spirit of Juniper. The former (Spiritus Juniperi, Br.) is prepared by dissolving a fluidounce of the oil of juniper in nine fluidounces of rectified spirit (alcohol); the latter (Spiritus Juniperi Compositus, U. S.), by dissolving the oils of juniper, caraway, and fennel, in diluted alcohol. By the Edinburgh and Dublin Colleges, it was directed to be made by distillation from the crude materials containing those oils. The compound spirit has an agreeable flavour; and both may be usefully added to diuretic infusions and mixtures, in cases of dropsy requiring a stimulant impression, whether on the stomach or the system. The dose of the simple spirit is from twenty minims to a fluidrachm; of the compound, which is much weaker, from two to four fluidrachms.