Illudin S is a potent cytotoxic compound primarily investigated for its role in cancer therapy. It functions by intercalating into DNA and generating reactive oxygen species, leading to DNA damage and apoptosis in rapidly dividing cells. Due to its high toxicity, Illudin S is not used directly as a drug but serves as a key precursor in the synthesis of less toxic, targeted anticancer agents. One of its derivatives, Irofulven, has advanced into clinical trials for treating solid tumors, including ovarian, prostate, and liver cancers. Its mechanism makes it particularly effective against tumor cells with impaired DNA repair mechanisms. Research also explores its potential in antibody-drug conjugates, where it can be delivered selectively to cancer cells, minimizing damage to healthy tissues.