Defining Poison ca. 1300–1600

Defining Poison ca. 1300–1600

By Frederick Gibbs, George Mason University

Given at the International Congress on Medieval Studies (2010) – Session: Poison and Medicine in the Fourteenth Century

This paper discussed the definition of poison and its growing medical interest throughout the 14th to 16th centuries.

What was poison in the Middle Ages? There were many kinds of poison but no clear medical definitions. Toxicology on poison emerged around 1300. Until 1300, medical writing about poison dealt with cases, how to recognize poison and deal with it but not about poison itself. In the 13th century, a new interest in poison emerged due to increase in trade in the Mediterranean and new philosophic discussions about mixing plants and herbs.

In 14th century Paris, a sharper distinction was made between poison and drugs in a work entitled Concordances. Discussions ensued around what was the minimum amount of a substance that could affect the body. The definition of poison was continually shaped over the course of the 14th century by writers of plague tracts. By the mid-14th century, poison becomes its own separate subject. Post Black Plague, the transference of poisonous property from animals to humans was of interest to writers.

In the 15th century, poison was defined as ‘that which operates between the complexion and occultic’. Sante de Arduino wrote that ‘poison is that which corrupts the complexion and substance’. There were many contradictory definitions and a lot of scholastic “intellectual jousting” as poison grew to be a very important topic.

During the 16th century, there was a shift in how physicians thought about poison.  Physicians looked at the substances and properties of poison and its effects. Ferdinand Ponzetti questioned if elements (earth, air, fire, water) were poisonous. This spawned literature on toxicology about the notion of change in the body, putrefaction, and contamination of others.

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