Three residents of New Jersey suddenly developed vomiting, abdominal pain, and watery diarrhea 12 h after ingesting five to 13 hand-pickedAmanita phalloides–type mushrooms. The group was led by an amateur mycologist who had been eating hand-picked mushrooms without complications for 20 years. The patients developed mild to severe acute hepatic injury, with a peak serum aspartate aminotransferase level ranging from 133 to 826 Karmen U/L, and a peak serum alanine amino-transferase level ranging from 163 to 1176 Karmen U/L. One of the patients developed a transient severe coagulopathy, but no one developed renal failure or hepatic coma, and all rapidly improved. These three cases demonstrate that mycetismus can occur in the heavily urbanized northeastern United States, that consuming handpicked mushrooms even under the guidance of an experienced amateur may be dangerous, and thatAmanita phalloidesingestion produces a biphasic illness with early gastrointestinal symptoms and subsequent hepatic injury.