Although ergot of rye causes yield reductions, the significance of the disease is primarily related to the various toxic alkaloids present in the ergots (sclerotia). The alkaloids can cause severe health problems in both humans and animals. Before this disease was understood, the ergots were ground up along with rye grains and ingested when the flour was used for baking. In the Middle Ages, this led to a frightening disease of humans known as "holy fire" or "St. Anthony’s fire." Today, ergot poisoning is mostly a concern in animals that may be given contaminated feed or graze where wild grasses are heavily infected with ergot.