Medicinal resins, sometimes termed resinoids or concentrations, are a class of agents obtained from medicinal plants or roots, etc., by precipitation from their alcoholic tinctures, either by means of water alone, or aided by distillation. Those at present in use are generally impure, and contain one or more, but not all, of the therapeutic virtues of the plants from which they are made. Note.—The "Strong Tincture" of the different resins, referred to in their preparation, is usually made by exhausting any quantity of the root, or bark, etc., of the crude agent, by percolation with official alcohol. The subsequent evaporation is to be carried on by distillation until the residue is of a syrup consistence. Most of the Eclectic resinoids are now discarded in favor of liquid preparations of the drugs yielding them, but, for obvious reasons, it is best to record again the processes to be found in former editions of this work. Resinoids, as a rule, are no longer of importance to Eclectic physicians. The exceptions to the above remarks are resins of cimicifuga and podophyllum. and the alkaloids found in hydrastis and sanguinaria, which were introduced originally as Eclectic resinoids.