Ordeal By Host
In the Catholic Church, people eat the Eucharist every Sunday during mass. The Eucharist is a bread wafer that is supposed to symbolize the body of Jesus Christ, and red wine represents his blood. This comes from the Bible verse Matthew 26:26 when Jesus was speaking to his Apostles during the Last Supper, and he instructed them to eat the bread and blood as a representation of his flesh.
In Medieval Times, people truly believed that a priest had the power to turn the bread and wine into the flesh of Jesus. Even to this day, devout Catholics truly believe in the act of “transubstantiation”, which was a term invented during the Middle Ages. Even back then, there was a debate as to whether the transformation was literal, or symbolic. Either way, it is a sacrament, or requirement for every member of the church. Consuming the Eucharist provides a direct communication with God, and an opportunity for someone to say their prayers as the wafer dissolves on their tongue. Once someone consumed the wafer, they were exposing their soul to God to judge them for their sins. This was why people were encouraged to confess their sins to the priest before they receive communion.
It only makes sense, then that priests decided they would use this belief to their advantage whenever one of them committed a crime. Instead of enduring torture like the common people, a priest would hold the Eucharist and declare that if they were guilty, God would make him choke when he ate the bread. There were a few times when people had a psychosomatic reaction to swallowing the wafer, because their guilt over their deed, combined with the fear that God was going to smite them was enough to make them panic and start to choke.