This section is from the book "An Experimental History Of The Materia Medica", by William Lewis.
Pareira Brava Pharm. Lond. Pareyra, Ambutua, Butua, Overo brutua, Zan. hist. Pharm. Paris. Pareira brava: the root of an American climbing plant (convolvulus bra-zilianus flore octopetalo monococcos Rait hist, Ciffampelos Pareira Linn.) brought from Brazil, generally in crooked pieces of different sizes, some no bigger than the finger, others as large as a child's arm: the outside is brownish and variously wrinkled; the internal substance of a pale dull yellowish hue, and interwoven as it were with woody fibres, so that on a transverse section, there appears a number of concentric circles, crossed with striae running from the centre to the circumference.
This root is extolled by the Brafilians and Portuguese in a variety of diseases, particularly in suppressions of urine and in nephritic and calculous complaints. Geoffroy is of opinion, that its virtue consists in dissolving and attenuating tenacious juices; and reports, that in sundry disorders arising from their viscidity, it was found remarkably beneficial: that in nephritic pains and suppressions of urine, he has often given it with happy success: that he has sometimes seen the patient freed from pain almost in an instant, and a plentiful discharge of urine brought on: that in ulcers of the kidneys and bladder, where the urine was mucous and purulent, and could scarcely be voided, or not without great uneasiness, the symptoms were soon relieved by pareira, and the ulcer at length healed by joining to it balsam of copaiba: that in an asthmatic case, where the patient was almost suffocated by thick phlegm, an infusion of pareira, after many other medicines had been tried in vain, brought on a copious expectoration, which proved a solution of the disease: that a person who, from an acute pain under the liver, had become in a few hours icterical, had the pain relieved, after bleeding, by the third cup of the decoction, and all the symptoms removed by a continuance of it; and that the same disorder frequently returning, she always found relief from the same medicine: but that in another icterical case, where the liver was swelled, it did no good. He cautions against giving too large doses, which might, he observes, raise a heat, and perhaps an inflammation in the kidneys: of the root in substance he prescribes from twelve grains to half a dram, and in decoction or infusion two or three drams; this quantity of the root, bruifed, he directs to be boiled in a pint and a half of water till only a pint remains, which is to be (trained off, sweetened with a little sugar, divided into three portions, and drank as tea at intervals of half an hour.
The use of this root has not been in general accompanied with so much success: but though, like many other medicines, it has not been found to answer the character at first given of it, and has thence fallen into neglect, we may presume, from its sensible qualities, that it is not destitute of medical virtue. It has no remarkable smell; but to the taste it manifests a notable sweetness, of the liquorice kind, together with a considerable bitterness and a slight roughness covered by the sweet matter. It gives out great part both of the bitter and the sweet substance to watery and spirituous men-strua: in evaporating the watery decoction, a considerable quantity of resinous matter sepa-rates, which does not mingle with the remaining extract or dissolve in water, but is readily taken up by spirit; whence spirit appears to be the most perfect dissolvent of its active parts. Both the spirituous tincture and extract are in taste stronger than the watery.