Guayaco (guaiac, the palo de las Indias)
The first American remedy to become a European blockbuster, and the first to be discredited. Guaiac wood reached Spain by 1508 as the pox spread, was sold as lignum sanctum, was cornered by the Fuggers in return for a loan to the crown, landed at Seville by the ton — and did not work. It belongs in the record of the American materia medica beside cinchona, because the transfer that failed is what makes the transfer that succeeded measurable.
Why this wins its question: Guaiac normally survives as a footnote — a line in a syphilis chapter, a Fugger anecdote in a banking history, or an example of Renaissance credulity. Nobody assembles the money, the medicine and the patient in one place. This object does, from two peer-reviewed open-access studies: the loan that bought the monopoly, the tonnage through Seville, what a course cost against a labourer's wage, what the cure physically consisted of, the Spanish poem that praised the wood while eviscerating it, the contemporary judgement that it was useless, and the trade ledgers in which it vanishes while cinchona climbs. The point is not that Spain exported a bad drug. It is that the same Seville pipeline carried both, and the corpus that claims cinchona has to carry guaiac too — which is precisely what makes the cinchona claim worth believing.
Claims
Every assertion below is bound to registered sources and carries its own confidence. Weight them; do not treat the page as uniformly authoritative.
Guaiac wood entered Spain by 1508, arriving as the disease then called the French pox was spreading, and it was marketed under names that made the claim before any physician did — lignum sanctum, the holy wood, and lignum vitae, the wood of life.
The promotion was official as well as commercial. Numerous treatises advertised the wood's miraculous properties, and the medical establishment and the crown encouraged trials of it through the Casa de la Contratación — the same Seville institution that controlled the American trade.
The money is on the record and belongs beside the medicine. The Fugger banking house secured a monopoly on guaiac in exchange for a large loan that helped support the Spanish throne. The remedy's distribution in Europe was therefore a financial instrument of the Spanish crown's borrowing before it was a therapeutic question.
The traffic was substantial: more than 21 tons of guaiac reached Seville between 1568 and 1608. Two independent scholarly accounts give the same figure for the same window, one reading it as the measure of the boom and the other as the last of it before the collapse.
Treatment was expensive enough to be a household event. In late sixteenth-century Florence one course of guaiac therapy could cost between 2 and 13 per cent of the annual earnings of an unskilled construction worker. The figure is Florentine rather than Spanish and is offered here as an order of magnitude, not as a price in Castile.
The regimen itself was punishing. In the account left by Ulrich von Hutten, the patient was "kept in a close chambre, withoute ayre or wynde, where fyre muste be nourished contynually", for more than thirty days, on a restricted diet and under heat therapy.
The most exact contemporary Spanish witness is a poem. Cristóbal de Castillejo (1490?–1550) wrote "En alabança del palo de las Indias, estando en la cura dél" — in praise of the wood of the Indies, while undergoing the cure of it — as a mock encomium that praises the remedy and undermines it in the same breath, and ends on the patient rather than the drug: bread and raisins, barely six or seven ounces as the largest portion, hot and bitter water, and a bed in which he roasts.
The wood did not work, and this was noticed at the time. Its popularity faded in the latter half of the sixteenth century; Paracelsus refused to credit its miraculous properties and pronounced it useless; and the apparent improvement patients showed on guaiac is attributable to the discontinuation of the mercurial therapy it replaced, whose symptoms abated once the mercury stopped.
The commercial record closes the case. Guaiacum, hailed as an anti-syphilitic in the early sixteenth century, fell from favour because "people suffering from syphilis were not benefited by its administration"; Spanish imports fell from the 21 tonnes of 1568–1608 to negligible eighteenth-century volumes and disappeared from Spanish trade records altogether, while cinchona in the same records rose to 201 tonnes in 1789.
The knowledge behind the American remedies was indigenous, and the credit for it moved. The remedies that entered world trade rested on the understanding and experience of Andeans, Tupi-Guaraní or Araucanians in identifying, collecting and preparing them; but by the eighteenth century that indigenous knowledge had become, in the words of the study, "a cultural trope, a discourse, for European naturalists, merchants and officials to capitalise on" — invoked as a warrant for a remedy's value rather than acknowledged as expertise. This claim is made of the American materia medica as a class; the sources read here do not name a specific indigenous informant for guaiac itself.