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.
Fennel-seed is the fruit of Foeniculum vulgare (De Cand.), F. officinale (Merat and De Lens), and possibly F. dulce (De Cand.). These are perennial umbelliferous herbs, growing wild in the South of Europe and in Asia Minor, and cultivated both in Europe and the United States. The whole plant, in the different species, has a grateful aromatic odour and taste, on account of which F. dulce is cultivated in Southern Europe; the shoots being eaten raw, or in the form of salad.
Sensible Properties. Fennel-seed consists usually of the separated half-fruits (mericarps) of the plant, usually called seeds. These are oblong-oval, flat on one side and convex on the other, occasionally connected by their flat surfaces, and of a grayish-green colour, with yellowish longitudinal ridges on the convex surface. There are two varieties, one smaller, a line or two in length, always in separate half-fruits; the other larger, three or four lines long, of a lighter colour, more prominent ridges, often connected together forming whole fruits, and with a short footstalk. The former comes probably from F. vulgare, the latter from F. officinale. Both have a pure aromatic odour and taste, peculiar and very agreeable. They impart their sensible properties and virtues to water and alcohol, but more largely to the latter.
Active Principle. Fennel-seed depends for its activity exclusively on a volatile oil, which is obtained by distillation with water, is lighter than water, colourless or yellow, and of a very grateful flavour.
The ancients were acquainted with this medicine. It is purely aromatic, mild in its action on the stomach, and scarcely stimulant, in ordinary doses, to the system at large. Being less heating than cloves, cinnamon, ginger, or even cardamom, and yet of a very grateful flavour, it is preferable to these aromatics, when there is an indication at the same time for their peculiar influence, and for the avoidance of over-excitement, whether local or general. In the form of infusion, or of fennel water, it is often employed in infantile cases to relieve flatulent colic, and to obviate nausea. It may sometimes be useful for the former purpose, given as an enema. It is one of the best additions to purgative medicines, and is often associated with senna, rhubarb, and magnesia, in infusion or mixture.
An Infusion may be made in the proportion of two drachms to a pint of water, and given in the dose of two or more fluidounces to an adult, and two or three fluidrachms to an infant.
The Volatile Oil (Oleum Foeniculi, U.S.) may be used in doses of from five to fifteen drops as a carminative or antiemetic; and may be associated with other substances in pill, lozenge, or confection, to give them flavour, or enable them to sit better on the stomach.
Fennel Water (Aqua Funiculi, U. S.) is made by dissolving the oil in distilled water, by the instrumentality of carbonate of magnesia. In the British Pharmacopoeia, it is directed to be made by distilling water from the seed; and the same directions are given in our national code as an alternative process. The dose for an adult is one or two fluid-ounces, for an infant as many fluidrachms. It is a very good vehicle for medicines given in the form of mixture.
There are several other aromatic fruits, the medical properties and uses of which so closely resemble those of fennel, that what is said of one may be nearly as well said of all; one being preferable to another, mainly from its according better with the taste or stomach of the patient. It is unnecessary, therefore, to do more than name them, and very briefly describe their origin and distinctive physical properties