Pleurotus ostreatus
This fungus is mistaken for the commonly eaten oyster mushroom ("Pleurotus ostreatus"), Shiitake ("Lentinula edodes"), and Mukitake ("Sarcomixa serotina"), but is poisonous. "O. japonicus" was responsible for 31.6% of poisoning cases in Japan between 1996 and 2005—more than any other mushroom. Symptoms of "O. japonicus" poisoning are nausea, vomiting and diarrhea. The most common treatment is fluid therapy.