Botanical name: 

The dried rhizome and roots of Gentiana lutea, Linné (Nat. Ord. Gentianaceae.) Common in the mountainous regions of southern and central Europe. Dose, 10 to 30 grains.
Common Names: Gentian, Gentian Root.

Principal Constituents.—Gentiopicrin, an active, bitter glucoside, associated with gentisic acid or gentisin (C14H10O5). No tannin is present but a coloring matter which is darkened by iron compounds.
Preparations,—1. Infusum Gentianae, Infusion of Gentian. Dose, 1 fluidrachm to 1 fluidounce.
2. Specific Medicine Gentiana. Dose, 5 to 30 drops.
3. Tinctura Gentianae Composita, Compound Tincture of Gentian. (Contains Gentian 10 percent, Bitter Orange Peel, and Cardamon.) Dose, ½ to 1 fluidrachm.

Specific Indications.—Sense of epigastric depression, with physical and mental weariness; atony of stomach and bowels, with imperfect digestion.

Action and Therapy.—Gentian is one of the best of the simple bitter tonics, for the action of which compare Calumba. In large doses, however, it is capable of deranging digestion, with the production of nausea, vomiting, and diarrhoea, and fullness of the pulse, with headache. It is contraindicated in gastric irritability or inflammation.

The chief use of gentian is to promote the appetite and improve digestion in states of chronic debility. This it does when given in moderate doses. For atony of the stomach and bowels, with feeble or slow digestion, it is an ideal stimulating tonic; and after prolonged fevers and infections, when the forces of life are greatly depressed and recovery depends upon increased power to assimilate foods, gentian may be used to improve gastric digestion and thus hasten the convalescence. Gentian is especially useful in anorexia, in the dyspepsia of malarial origin, and in subacute gastritis and intestinal catarrh. The infusion and the compound tincture of gentian may be used alone or as vehicles for other medicines.

The Eclectic Materia Medica, Pharmacology and Therapeutics, 1922, was written by Harvey Wickes Felter, M.D.