A phytochemical investigation to identify inducers of increased aryl hydrocarbon hydroxylase (AHH) activity from three cruciferous vegetables, Brussels sprouts, cabbage, and cauliflower, resulted in the identification of indole-3-acetonitrile, indole-3-carbinol, and 3,3'-diindolylmethane as naturally occurring inducers. These compounds are produced during the hydrolysis of indolyl-methyl glucosinolate by the plant enzyme myrosinase.