In 1875 and 1876, he wrote papers advocating the use of sub-emetic doses of ipecacuanha in the treatment of dysentery.
He first conceived the idea of making the culture of the Ipecacuanha meaning “sick making plant” - Ipecac Syrup of ipecac tree a source of profit to the colony and had thousands of them planted, thus opening to Brazil a new branch of trade.
He discovered that emetine, the active ingredient of the ancient emetic ipecacuanha, is an amoebicide and therefore effective against amoebic dysentery.
Tradition states that El Almendro was founded in 1892, when Nery López, Perfecto Romero Acosta, Francisco González, and others, searchers of rubber trees and growers of Ipecacuanha (known locally as raicilleros) arrived looking for rubber and Ipecacuanha (known locally as raicilla).
:For the plant species commonly known as Ipecacuanha, see Carapichea ipecacuanha
According to reports in the book, besides studying tropical diseases and indigenous therapies (including the use of Ipecacuanha-root and leaves of the Jaborandi), Piso collected plants and animals in Brazil.