The orally bioavailable calcium salt of glucaric acid, a natural substance found in many fruits and vegetables, with potential chemopreventive activity. After absorption, glucaric acid is converted to d-glucaro-1,4-lactone which inhibits beta-glucuronidase, an enzyme found in certain bacteria that reside in the human gut. The detoxification of various toxin and sex hormone metabolites depends upon their conjugation to glucuronic acid in the liver and subsequent excretion of glucuronic acid conjugated metabolites in the bile. Bacterial beta-glucuronidase may catalyze the deconjugation of glucuronic acid conjugated metabolites of toxins and sex hormones, thus prolonging exposure to unconjugated and unexcreted toxin and sex hormone metabolites. Accordingly, calcium glucarate supplementation may indirectly inhibit sex hormone-mediated and toxin-mediated tumorigenesis by inhibiting bacterial beta-glucuronidase activity. Elevated bacterial beta-glucuronidase activity may be associated with an increased risk for sex hormone-mediated and toxin-mediated cancers such as breast, prostate, and colon cancers.