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The frequency and severity of dysentery and hepatic abscess during the colonial and republican era in Chile are reviewed. The amebian etiology was confirmed in both clinical entities. Also, Miguel Claro Vásquez, physician and later priest and bishop of the Catholic Church, was distinguished for his contribution to hepatic abscess surgery.

The story of ipecacuanha, derived from the plant Cephaelis, is a fascinating one. It was discovered in Brazil in the 1600s and then transported to Paris in the latter part of the same century. It was used there by the physician Helvetius on various members of the French royal court to treat the flux (dysentery) with some success. Later, in the eighteenth century, it was taken up by the physician and privateer Thomas Dover and became, with opium, a fundamental constituent of his celebrated powder, which was used widely to treat fevers and agues for the next 200 years. Progress was then delayed until the early 1800s when the School of Chemistry at Paris established that the dried root of ipecac contained two powerful alkaloids, emetine and cephaeline, that consistently caused vomiting and diarrhoea. The discovery of the pathogenic amoeba, Entamoeba histolytica, in the latter part of the nineteenth century, allowed a distinction to be made between the two main forms of dysentery (amoebic and bacillary). Emetine was shown to be active against the amoebic form of dysentery but ineffective against that caused by bacteria. Ipecacuanha, its root and the pure alkaloid emetine have now been abandoned on the grounds of toxicity. They have been replaced by safer, more effective compounds. Nevertheless, they deserve an honoured place in the history of medicine, especially in the search for an effective treatment for amoebic dysentery.

This article presents a history of Entamoeba histolytica spanning since the remote times when it was not even recognized as a cause of human disease to the recent molecular advances. Feder Losch (1875) in Saint Petersburg, found amoebae in fecal samples but only regarded them as responsible for maintaining the inflammatory process, not as a cause of dysentery. Fritz Schaudinn (1903) established the differentiation between Entamoeba histolytica and Endamoeba coli, Schaudinn decided to call it E. histolytica because of its ability to cause tissue lysis. Emile Brumpt (1925) based on experimental studies, pointed out the existence of E. Histolytica as a species complex, comprising two morphologically indistinguishable species, E. dysenteríae which is the cause of symptomatic infection, and Entamoeba dispar found only in asymptomatic carriers. Louis Diamond et al (1961) during the 1960s developed an axenic culture medium for E. histolytica which allowed in vivo and in vitro studies. Sargeaunt and Williams (1978) distinguished for the first time E. histolytica strains by isoenzyme electrophoresis, thus confirming that E. hystolytica was indeed a species complex comprising both pathogenic and non-pathogenic species. William Petri et al (1987 demonstrated that the 170 kDa protein with greater antigenicity was the Gal/GalNac-specific lectin. Diamond and Clark (1993) described again Brumpt's original 1925 hypothesis, concluding that there was enough evidence to support the existence of two morphologically indistinguishable species, a pathogenic and a nonpathogenic one, corresponding to E. histolytica and Entamoeba dispar respectively. The World Health Organization accepted this hypothesis in 1997.