The raíz de Mechoacán, the "ruybarbo de las Indias"
A purgative root from the province of Michoacán that a Purépecha healer gave to a sick Franciscan around 1550, and that within thirty years was being sold in Seville by the quintal under the borrowed name rhubarb of the Indies. The Sevillian physician who publicised it prints both halves of the story: an indigenous prescription that displaced the violent purges of European practice, and a trade so intent on its profit that nobody in Spain could describe the plant the root came from.
Why this wins its question: In English the Mechoacán root survives, when it survives at all, as a synonym in a materia medica list — "jalap, Mexican rhubarb" — with no document behind it. This object works from the 1580 Seville printing itself and quotes the pages: the indigenous physician who prescribed it first, the friar who was the patient, the Provincial who distributed it, the European drug whose name it took, the ten quintales one druggist moved in a year, the reason Monardes could not describe the plant, and his own written reproach that no one was studying the medicines sold in the tianguis. Credit, commerce and the gap in the knowledge, all from the same page — and the modern botanical identification deliberately withheld, because the source does not supply it.
Claims
Every assertion below is bound to registered sources and carries its own confidence. Weight them; do not treat the page as uniformly authoritative.
Writing at Seville in the collected edition of 1580, Nicolás Monardes opens his chapter "Del Mechoacan" by stating that it is a root discovered some thirty years earlier in the province of New Spain, brought from a region more than forty leagues beyond Mexico called Mechoacán — the province, he adds, that Hernán Cortés conquered in 1524, and a land rich in gold and above all in silver.
The account he prints of how the root reached Spanish hands credits an indigenous physician, not a Spaniard. Franciscans who founded a monastery in the province after its conquest fell ill, among them the Guardián, whose close friend was "Caçoncin Cacique, y señor de toda aquella tierra"; seeing the friar's long illness worsen, the cacique offered to bring him an Indian of his own who was a physician and with whom the cacique treated himself. The physician came, saw the illness, and told the cacique that if the sick man took certain powders of a root that he would give him, he would be cured. The friar took them next day in a little wine, purged "tanto y tan sin passion" that he was relieved that same day, and recovered; other friars and some Spaniards who were also ill took the same powders, and all of them were cured.
The same passage records that the province was a place of resort for the sick before the Spaniards arrived: Monardes writes that its airs are healthy and its herbs salutary, so much so that "en tiempo delos Indios, los comarcanos venian a ella, para sanar de sus males y enfermedades", and that its principal town, on a fresh-water lake, "llaman los Indios en su lengua Chincicila" while the Spaniards call it Mechoacán after the whole kingdom. The description is second-hand, from a man who never saw the place.
Distribution was institutional from the start: the friars sent a relación of the cure to their Provincial in Mexico, who gave out the root to people of the country and encouraged them to take it on the strength of the reports from Michoacán, and its reputation spread until, in the words of the same page, the whole land was full of its praises and good effects.
Its success was measured against an existing drug and it took that drug's name. Monardes writes that the root banished the use of the rhubarb of Barbary and took its name, being called "Ruybarbo de las Indias", the name he says everyone commonly used, and also Mechoacán after the province it was gathered in; and that in Peru and throughout the Indies they purged with nothing else, carrying it from New Spain as "mercaderia muy preciada".
The same book records that the older purgatives it competed with — including the milky latex of the plant the Indians called pinipinichi — were "violentas y de gran furia" and had been abandoned since the Mechoacán arrived, "porque enel se halla obra mas segura". The comparative judgement is Monardes's own and rests on the humoral medicine of his century.
By 1580 it was an article of ordinary commerce. Monardes reports that a Seville druggist told him that, over and above what he had sold inside the city, he had sold more than ten quintales of it out of the city in the previous year, and that buyers asked for it by the name rhubarb of the Indies; there was no village where it was not used, "como medicina segurissima", and part of its appeal was that for it "no han menester Medico".
The cost side is stated by the same witness. Monardes writes that he had questioned many who came from New Spain about the form of the plant and could learn nothing, because those who handle it "lleuan el principal intento al interes y a sus ganancias": the Indians of Michoacán sell the roots dried and cleaned, the Spaniards buy them, and they are shipped to Spain as a kind of merchandise, with the botany left unrecorded at both ends.
He turns the reproach on his own profession: "y cierto en esto somos dignos de muy grande reprehension", that with so many herbs and plants of importance in New Spain there is nobody who writes of them nor any knowledge of what virtues and forms they have to compare with European ones — and that it would be of great utility to investigate and experiment with the medicines the Indians sell in their markets, "o Tianges".
What this object does not claim. The identification of the root with any modern botanical species is not asserted here, because the source read does not make it: Monardes states twice that he had been unable to learn what the plant looked like. His therapeutic claims are those of sixteenth-century humoral practice and no modern verdict on the drug is cited. He never crossed the Atlantic, wrote at Seville from the testimony of men arriving with the cargoes, and belonged to a city whose physicians and merchants had a direct interest in the American drug trade.