Botanical name: 

The rhizome and rootlets of Coptis trifolia, Salisbury. (Nat. Ord. Berberidaceae.) A plant of dark, cold swamps and sphagnous woods, found in Siberia, Greenland, and Iceland, and in the United States, following the Appalachians as far south as Alabama.
Common Names: Gold Thread, Mouth Root, Canker Root.

Principal Constituents.—Two alkaloids: berberine (yellow) and coptine (white). It is devoid of starch, tannin or resin.
Preparations—1. Decoctum Coptis, Decoction of Coptis. (Coptis, 2 drachms, to Water, 16 ounces.) Dose, 2 to 6 fluidrachms. Used freely as a local wash.
2. Tinctura Coptis, Tincture of Coptis. (Coptis, 1 ounce; Diluted Alcohol, 16 ounces) Dose, 30 to 60 drops.
Specific Indications.—Aphthous ulceration; atonic dyspepsia; thrush.

Action and Therapy.—External. The most effective application for thrush in infants. The decoction should be freely applied and at the same time given internally. The infusion or the tincture may be used, with or without hydrastis, in aphthous ulcers of the mouth.

Internal. Coptis is a pure bitter and one that ought to be more generally used. It ranks with quassia, calumba, gentian, and similar agents in efficiency and may be used for many of the purposes for which hydrastis is employed. Its use in the stomachic disorders associated with, preceding or following thrush is the most certain in therapy, and its internal employment hastens the local cure, which it quickly accomplishes. Coptis is a good stimulant for atonic indigestion and dyspepsia, with deficiency in the normal flow of the peptic juices.

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