Illudin

The illudins are a family of sesquiterpenes with antitumor antibiotic properties produced by some mushrooms. In their isolated form, illudins show selective toxicity for myelocytic leukemia and other carcinoma cells.
Illudin is highly toxic, with little apparent therapeutic value in its natural form. It is thought responsible for the ill effects caused by various Omphalotus species like O. olearius and O. illudens (Jack 'o' Lantern mushrooms), and O. nidiformis (Australian ghost fungus).