Before the development of modern medical tests and anti-microbial drugs, the problem of food poisoning was often a matter of guesswork. Medieval people tended to worry less about it because their understanding of the nature of food hygiene was imperfect. As a result, they tended to suspect that the enemy had laced the food they ate with noxious mixtures. However, this was not always the case.
The first emperor of Constantinople, Henri of Flanders, was concerned about the potential effects of food poisoning on his future heir, Edward VI. As a precaution, he ordered tasters to test his future meals. The emperor also commanded the soldiers of his household to keep a safe distance from the food they were about to serve. This was done to ensure that no one was inadvertently approaching the food, which was likely to have been highly contaminated.
In the late Middle Ages, the focus on health care was not as great as it is today. The medieval people had a different set of priorities, as they were caught in cycles of grain seizure to feed their troops in endemic wars. Because food was precious to all, making sure people had the best food possible was as important as ensuring that they had enough food. As a result, the study of medieval societies has uncovered a “moral economy” that emphasized profit as well as the broad definition of charity.
The spread of poisons became widespread in Medieval Europe. Several well-known poisons were used to cure illnesses. As a result, apothecaries began selling their medicinal wares to the public. Traditional medicinal substances were used for far more sinister purposes, and even developed new ones. The Arabs had a odorless, transparent form of arsenic, which was used for a variety of purposes. Eventually, the plague spread to parts of Asia and even the Middle East.