Active Ingredients. - Mezereon bark contains daphnine, a resin, and a volatile oil. The daphnine is a neutral crystalline principle, bitter, and slightly astringent, but inert; the resin is dark green, acrid, and soluble in alcohol and in ether; the volatile oil is acrid and highly irritant. Upon this, in conjunction with the resin, depend the active properties. When mezereon root is boiled in water an acrid vapor is given off.

Physiological Action. - That the mezereon is a poisonous plant appears incontrovertible. The berries have long been known to be highly dangerous, and, in a case recorded by Linnaeus, are said to have caused death. The bark of the root (and of the stem also, but in a less degree) is excessively caustic. Chewed, it gives at first an impression of sweetness, but an acrid and burning sensation soon arises in the mouth and fauces, lasting for several hours; and if the impregnated saliva be swallowed, or any portion of the bark itself, the burning extends to the throat and stomach. Pereira says that "all parts" of the plant, " swallowed in large quantities," ..."prove poisonous." The topical action of the bark is that of an irritant, and, when applied to the skin, that of a vesicant. A decoction, taken internally, appears to promote the action of the skin and of the kidneys; but Dr. Alex. Russell disputes these effects. In large doses it causes irritation both of the kidneys and of the alimentary canal.

Decoction of mezereon bark often proves laxative. In some constitutions it increases the flow of saliva, and causes pain in the stomach and bowels; and sometimes vomiting and purging.

Therapeutic Action. - Mezereon bark has been very strongly recommended in rheumatic and scrofulous diseases; also in chronic cutaneous disorders, and in cases of syphilis.

There would, however, seem to be some uncertainty in its action; or perhaps certain constitutions only are open to its effects. Mr. Pearson absolutely denies the utility of mezereon in relation to syphilitic disease in any form or in any stage.

It has also been resorted to with good effect as a cure for toothache, and as a masticatory in cases of paralysis of the tongue.

Preparations and Dose. - Extract. Mezerei Fluid., m v. - xxx. (.30 - 2.); Ungt. Mezerei; also an ingredient of Decoct. Sarsap. Co. and Syr. Sarsap. Co.