This article outlines the history of the commerce in medicinal plants and plant-based remedies from the Spanish American territories in the eighteenth century. It maps the routes used to transport the plants from Spanish America to Europe and, along the arteries of European commerce, colonialism and proselytism, into societies across the Americas, Asia and Africa. Inquiring into the causes of the global 'spread' of American remedies, it argues that medicinal plants like ipecacuanha, guaiacum, sarsaparilla, jalap root and cinchona moved with relative ease into Parisian medicine chests, Moroccan court pharmacies and Manila dispensaries alike, because of their 'exotic' charisma, the force of centuries-old medical habits, and the increasingly measurable effectiveness of many of these plants by the late eighteenth century. Ultimately and primarily, however, it was because the disease environments of these widely separated places, their medical systems and materia medica had long become entangled by the eighteenth century.