Contrayerva has been omitted in the present Pharmacopoeia. It is the root or rhizome of Dorstenia Contrayerva, a small perennial plant, growing in the West Indies, Mexico, and Peru. As in the shops, it is of a somewhat oblong shape, an inch or two in length, rough, very hard, reddish-brown externally, pale internally, and furnished with numerous long, slender, yellowish radicles, attached to the lower part. The odour is aromatic; the taste warm, pungent, and bitter. Boiling water or alcohol extracts its virtues, which probably depend on a volatile oil, and a bitter principle, though the latter has not been isolated.

In its effects on the system, it is gently tonic, aromatic, stimulant, and diaphoretic, bearing some resemblance to serpentaria, but less powerful as a tonic. It was formerly used in low febrile diseases disposed to assume a typhous or malignant character, in dysentery and diarrhoea with debility, and in other conditions supposed to call for stimulation; but it has given place to more convenient or efficient remedies, and is now Scarcely used. The dose of the powder is from twenty to thirty grains. An infusion, made in the proportion of an ounce of the bruised root to a pint of boiling water, may be given in doses of one or two fluid-ounces.