Contrayerva
In botany, the contrayerva, or contrajerva, is the root and scaly rhizome of various tropical American species of Dorstenia in the family Moraceae (D. contrayerva and D. braziliensis[1]), a South American plant, the aromatic root of which is sometimes used in medicine as a gentle stimulant and tonic[2]. It was previously used as an antidote to snake bites.[3]
The name is used in Jamaica to refer to a species of Birthwort (Aristolochia odoratissima) still believed to have antidotal properties.[1]
The root is smaller than that of the iris, reddish outside and white inside, knotty, and fibrous. To be of use, it must be new, heavy, and of a dusky red color. Its odor resembles that of fig leaves. Its taste is aromatic, accompanied with some acrimony.[3]
The contrayerva root was formerly considered by many writers to be one of the best anti-epidemics known. Dr. Nathaniel Hodges (1629–1688), in his treatise of the Great Plague of London (Loimologia; published in 1672), had a recipe which he said was very successful, and of which this root was one of the chief ingredients.[3]