3,3’-Diindolylmethane (DIM) is a bioactive metabolite of indole-3-carbinol, a phytochemical produced by the breakdown of the glucosinolate glucobrassicin found in cruciferous vegetables. At 10-30 μM, it demonstrates anticancer and chemopreventative effects involving Nrf2 induction of Phase 2 enzymes, promotion of apoptosis, induction of cell cycle arrest, inhibition of cell proliferation, and inhibition of histone deacetylases and DNA methylation activities. Furthermore, at 0.3 μM DIM was shown to act as a potent radioprotector and mitigator of the effects of ionizing radiation exposure by stimulating an ATM-driven DNA damage-like response and NF-κB survival signaling in cultured epithelial cells.