Research indicates that protecting cells or tissues from carcinogens and carcinogenic metabolites through the induction of cellular defense enzymes, such as phase 2 detoxifying and antioxidant enzymes, is a method of chemoprevention that shows great promise. Antioxidant response element (ARE) is located in the promoter region of these defense genes and plays a key role in the induction of these enzymes. Many natural chemopreventive agents are known to induce ARE-mediated gene expression and regulate the upstream signalings involved in the ARE pathway.