This section is from the book "A Treatise On Therapeutics, And Pharmacology Or Materia Medica Vol2", by George B. Wood. Also available from Amazon: Part 1 and Part 2.
Our national standard recognizes as officinal, under the above titles, the roots of two species of Euphorbia; E. ipecacuanha and E. corollata, the former often called American ipecacuanha, the latter milkweed, from its milky juice; both herbaceous, perennial plants, growing abundantly in different parts of the United States.
Sensible and Chemical Properties. The roots often penetrate deeply into the soil, are two feet or more in length, sometimes nearly an inch in thickness, and, when dried, are light and brittle. They are of a yellowish or grayish colour externally, whitish within, inodorous, and of a feeble not disagreeable taste, perhaps somewhat sweetish, and followed by a slight sense of heat or acrimony in the fauces. They yield their virtues to water and alcohol. Their active constituent has not been isolated, but, as in other Euphorbiaceae, is probably an acrid principle. Their virtues are impaired by time.
in a full dose, these roots generally operate as an emetic with considerable energy, producing several discharges; the ipecacuanha spurge being somewhat milder, as generally thought, than the large-flowering. Both of them are apt to act on the bowels as well as to vomit; and sometimes, when given in the ordinary emetic dose, purge exclusively. They are not, like ipecacuanha, safe in overdoses; but, when taken too largely, act with great harshness, causing much nausea, violent vomiting, hypercatharsis, and symptoms of general prostration. They should not, therefore, be employed under ordinary circumstances; but may be resorted to, in the absence of other safer and more certain emetics, when vomiting is indicated. The dose is from ten to twenty grains, which may be repeated in twenty minutes if necessary. As a cathartic, they may be given in the dose of five or six grains, and as a nauseating expectorant and diaphoretic, in that of one or two grains.