This section is from the book "Materia Medica Pharmacy, Pharmacology And Therapeutics", by W. Hale White. Also available from Amazon: Materia Medica Pharmacy, Pharmacology And Therapeutics..
The root of Gentiana lutea Linne (nat. ord. Gentianeae).
Mountains of Central and Southern Europe.
In nearly cylindrical pieces or longitudinal slices, about 25 mm. thick, the upper portion closely annulate, the lower portion longitudinally wrinkled; externally deep yellowish-brown; internally lighter; somewhat flexible and tough when damp; rather brittle when dry; fracture uneven; the bark rather thick, separated from the somewhat spongy meditullium by a black cambium line; odor peculiar, faint, more prominent when moistened; taste sweetish and persistently bitter.
The chief constituents are - (1) Gentiopicrin, an active, very bitter glucoside, soluble in water and Alcohol. Can be split up into glucose and Gentiogenin. (2) Gentisic Acid, C14H10O5, in yellow, tasteless needles, united with Gentiopicrin. (3) A trace of a volatile oil. (4) Gentian-ose, a sugar. Gentian contains no Tannic Acid, but cannot be prescribed with iron, because that darkens the coloring matter.
Incompatibles. - Iron salts, silver nitrate, and lead salts.
Dose, 5 to 30 gr.; .30 to 2.00 gm.
1. Extractum Gentianae. - Extract of Gentian. By maceration and percolation with Water, and evaporation.
Dose, 2 to 10 gr.; .12 to .60 gm.
2. Extractum Gentianae Fluidum. - Fluid Extract of Gentian. By maceration and percolation with Diluted Alcohol, and evaporation.
Dose, 5 to 30 m.; .30 to 2.00 c.c.
Dose, 1 to 4 fl. dr.; 4. to 15. c.c.
Gentian has the same action as other bitters, such as calumba, and is employed for the same class of cases. It is more used than any other bitter, because its taste is pleasant and it is not astringent.