The rhizome and rootlets of Menispermum canadense.

Characters. - Rhizome several feet long, about a quarter of an inch (6 millimetres) thick, yellowish-brown or brown, finely wrinkled longitudinally and beset with numerous thin, rather brittle rootlets; fracture tough, woody; internally yellowish, with a thickish bark, a circle of porous, short, nearly square wood-wedges, and a large central pith; nearly inodorous; taste bitter.

Dose. - 5-20 gr. in infusion.

Composition. - It contains a small quantity of berberine and a colourless alkaloid.

Uses. - It acts as a bitter tonic, and is sometimes used also as a substitute for sarsaparilla.