Diindolylmethane (DIM) is an indole, a plant compound with health promoting properties, found in cruciferous vegetables.  As a phytonutrient (nutrient from a plant), DIM promotes healthy estrogen metabolism. By consuming cruciferous vegetables and/or taking DIM supplements, estrogen is broken down into its beneficial or good estrogen metabolites, known as 2-hydroxy estrogens.  As it increases the good estrogen metabolites, it also reduces the bad estrogen metabolites, known as 16-hydroxy and 4-hydroxy estrogens.  The more bad estrogen metabolites in your body, the greater your chances of estrogen dominance, which leads to breast cancer, particularly in post-menopausal women.  There is a test to determine how well you are metabolizing estrogen by measuring your good and bad estrogen metabolites.  This test is a urine test called 0142 Extronex.  You can take this test through a Naturopathic physician or order it directly from Life Extension Foundation (www.lef.org).