"Paxillus involutus" was widely eaten in Central and Eastern Europe until World War II, although English guidebooks did not recommend it. In Poland, the mushroom was often eaten after pickling or salting. It was known to be a gastrointestinal irritant when ingested raw but had been presumed edible after cooking. Questions were first raised about its toxicity after German mycologist Julius Schäffer died after eating it in October 1944. About an hour after he and his wife ate a meal prepared with the mushrooms, Schäffer developed vomiting, diarrhea, and fever. His condition worsened to the point where he was admitted to hospital the following day and developed kidney failure, perishing after 17 days.