ergotism
noun
er·got·ism ˈər-gə-ˌti-zəm 
: a toxic condition produced by eating grain, grain products (such as rye bread), or grasses infected with ergot fungus or by chronic excessive use of an ergot drug
Example Sentences
Recent Examples on the Web Experts now know that those symptoms are common among people with convulsive ergotism, or ergot poisoning, which is caused by a fungus that can grow on wheat, rye, and other similar grains. 
Sarah Klein, Health.com, 2 Oct. 2017
Sarah Klein, Health.com, 2 Oct. 2017 Word History
Etymology
borrowed from French ergotisme, from ergot ergot + -isme -ism
First Known Use
circa 1841, in the meaning defined above
Medical Definition
ergotism
noun
er·got·ism ˈər-gət-ˌiz-əm
: a toxic condition produced by eating grain, grain products (as rye bread), or grasses infected with ergot fungus or by chronic excessive use of an ergot drug