Trios'teum perfolia'tum, Fever Root, Fever-wort, Horse-gentian. -- The root (rhizome), U.S.P. 1820-1870; United States. Perennial herb 1-1.3 M. (3-4 degrees) high, hirsute; leaves pubescent beneath, 15 Cm. (6') long; flowers purplish, fruit dry yellow drupe, 12 Mm. (1/2') long. Root 15-20 Cm. (6-8') long, 15 Mm. (3/5') thick, knotty, brownish-yellow, bitter, nauseous; contains bitter principle, starch. Used as cathartic, emetic, diuretic, substitute for ipecac; in decoction, extract, infusion. Popular with Indians for fevers, amenorrhea. Dose, gr. 15-30 (1-2 Gm.).