The fresh leaves of Rhus Toxicodendron, Michaux; Rhus Toxicodendron and Rhus radicans, Linne.

Characters. - Long-petiolate, trifoliate; the lateral leaflets sessile, about four inches (10 centimetres) long, obliquely ovate, pointed; the terminal leaflets stalked, ovate or oval, pointed, with a wedge-shaped base; the leaflets entire and glabrous (in Rhus radicans, Linne), or variously notched, coarsely toothed or lobed, downy beneath (in Rhus Toxicodendron, Linne); when dry, papery and brittle; inodorous; somewhat astringent and acrid.

The fresh leaves abound with an acrid juice which darkens when exposed to the air, and, when applied to the skin, produces inflammation and swelling. The leaves should, therefore, not be touched with bare hands.

Rhus Toxicodendron should not be confounded with the leaves of Ptelea trifoliata, Linne, which are similar in appearance, but have all the leaflets sessile.

Composition. - It contains a volatile acid which appears to he the active principle.

Action. - In many persons, contact with this plant causes an eczematous eruption of a very distressing character, which is best treated by solutions of lead, permanganate of potassium, and ammonia. Internally it causes gastro-intestinal irritation, drowsiness, stupor, and delirium.

Uses. - It has been recommended in incontinence of urine, paralysis, and cutaneous diseases.

A fluid extract of a non-officinal plant, Rhus aromatica, has been used successfully in incontinence of urine in doses of 5 to 30 min.