A common belief is that the people had ingested a psychotropic known as ergot. Ergot grows on rye and when it is ingested it creates an effect in the human body known as ergotism. Ergotism, known as St.Anthony's Fire or the Holy Fire at the time, caused the muscles to spasm uncontrollably and makes the afflicted to contort and writhe in agony. (Wong,n.p.)
Rye was a commonly grown grain in France during the time that the dancing plague occurred, so it is easy to see why people would believe this was the cause of the epidemic. Rye was readily available in the area of the outbreak during the time it occurred. It was also eaten by nearly all of the poor in the area at the time due to its high availability. Ergot was also a common thing to grow on rye at the time. In fact, until the mid 1800's people believed that the ergot was a part of the rye.(Wong,n.p.) The cool, wet climate of Strasbourg, France is a prime spot for ergot to grow on rye. When ergot occurs it replaces the grain on the rye and the grain becomes a dark purple color. Ergot occurred more commonly during the wet season because the flower on the rye plant stayed open longer causing a larger likely hood of ergot growing. Strasbourg is located on the Rhine River which caused the rye crop to be exposed to more moisture, thus creating more ergot on the Rye. (Wong,