Contrayerva. Contrayerba. Contrayerve, Fr. Bezoarwurzel, Giftwurzel, G.—The root of Dorstenia Contrajerva L. (Fam. Urticaceae), a native of Mexico, the West Indies, and Peru. The term contrayerba, in the language of the Spanish Americans, signifies counterpoison or antidote, and was applied to this root under the impression that it had the property counteracting all kinds of poison. The probability is that the root sold as contrayerva is derived from several species of Dorstenia, among which, besides D. Contrajerva, two others are mentioned by Houston, D. Houstoni L. and D. Drakena L., the former growing near Campeachy, the latter near Vera Cruz, According to Pereira and Martius, the contrayerva of the shops is the product of D. brasiliensis Lam., and is brought from Brazil.
The root, as found in commerce, is oblong, an inch or two in length, of varying thickness, very hard, rough, and solid, of a reddish-brown color externally, and pale within; and has numerous, long, slender, yellowish rootlets attached to its inferior part. The odor is aromatic; the taste warm, slightly bitterish, and pungent. The rootlets have less taste and odor than the tuberous portion. The sensible properties are extracted by alcohol and boiling water. The decoction is highly mucilaginous. The tincture reddens infusion of litmus, and precipitates on the addition of water. Mussi (L'Orosi, 1894, 259) investigated this plant and found two substances, which he called provisionally cajapine and contrayerbine. Contrayerva is a stimulant tonic and diaphoretic, and has been given in low fevers, typhoid dysentery, and diarrhea, and other diseases requiring gentle stimulation. Dose, of powdered root, half a drachm (2 Gm.). In the root of the Gabbon ivy (Dorstenia klaineana?. Heckel and Schlagdenhauffen have found a coumarin-like body, pseudocoumarin. (Ph. Cb., xliii.)