Diindolylmethane (DIM) is produced when the substance indole-3-carbinol (I3C) is digested. Indole-3-carbinol, found in broccoli and other vegetables, has shown considerable promise for cancer prevention. Some of its benefits in this regard may occur after it is converted by the body to DIM.

DIM also has complex interactions with the hormone estrogen, which could lead to either positive or negative effects on cancer risk.

There is no dietary requirement for DIM. Good natural sources include broccoli, Brussels sprouts, cabbage, and cauliflower.