Poison Oak, or Sumach. Nat. Ord. Terebinthaceae. Linn. Syst. Pentandria Trigynia. Hab. North America, Japan, &c
Med. Prop. and Action. The leaves (off.) are stimulant, in doses of gr. 1/2, cautiously and gradually increased to gr. iv. daily, in the form of pill. in large doses, they are a powerful, acro-narcotic poison. The stems, when cut, exude a milky juice, which is said to produce inflammation of the skin when applied to it, and which turns black on exposure to the air. The whole plant evolves a deleterious vapour, which, in some persons, produces violent irritation, swelling, pain, &c. These properties depend upon an acrid principle, supposed to be a hydro-carbon. The leaves contain Gum Resin, Gallic and Tannic Acid, and a narcotic principle. (Royle.)
Dote of the powdered leaves, gr. 1/2 - gr. j.
Alderson, of Hull, and Dr. Duncan, It proved successful in four cases in which it was employed by Dr. Alderson; in each, a peculiar feeling of pricking or twitching preceded permanent benefit. This sensation was so unpleasant, that Dr. Duncan states that, on this account, he was obliged in one instance to discontinue the medicine. In general, it operated as a gentle laxative, notwithstanding the torpid state of the bowels of such patients. It may be commenced in doses of gr. j. of the dried leaves, and continued until gr. iv. - v. are taken daily, or until a pricking sensation is experienced in the affected part. Frictions with oil in which the leaves have been digested may be employed at the same time. Great caution is necessary in its use, and it is now almost discarded, being superseded by Strychnia. It has been employed in Neuralgia and Amaurosis, but with indifferent success.