The dried rhizome and roots of Hydrastis canadensis, yielding when assayed by the process given in the U. S. Pharmacopeia not less than 2.5 per cent, of hydrastin.

Action and Uses: Hydrastis is bitter and possesses the tonic and appetizing properties of other bitters. In addition it has been asserted that it has a special influence on mucous membranes, promoting their nutrition and favoring their return to a normal condition. For this property there is no experimental evidence, and in the opinion of some its existence is doubtful. The action of hydrastis on the circulation is not well understood, but it is believed that the drug stimulates the circulation and raises the blood-pressure. It has a stimulating influence on the uterus, and has been employed to check menorrhagia and metrorrhagia.