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.
Vanilla is one of the most agreeable of the aromatics; and it is singular that it should not have been sooner adopted by the Pharmacopoeias. It is now recognized only in our own. It is the fruit of the Vanilla aromatica and probably other species of the same genus, climbing plants, indigenous in Mexico, the West Indies, and South America. The fruit is a long slender pod, which is collected before maturity, dried in the shade, then covered with a coating of oil, wrapped, several pods together, in sheet lead, and enclosed in metallic boxes. The prepared fruit has an exquisite odour and taste, dependent on a volatile oil, which is said to be generated in the drying process, and cannot be obtained separate by distillation with water.
Vanilla, besides being aromatic, is probably somewhat stimulant to the nervous system. It is very much employed by confectioners for its agreeable flavour; but has not been much used in medicine. It has been recommended in low fevers, and in hysterical affections, usually in the form of infusion, made in the proportion of half an ounce to a pint of boiling water, and given in the dose of half a fluidounce. It should be employed, more frequently than it is, to flavour medicine and food for convalescents. Nothing so agreeably flavours chocolate, ice-cream, and liquid custard. The only preparation in which it is officinally employed are the Troches of Subcarbonate of Iron (Trochisci Ferri Subcarbo-natis, U. S.).