Grapefruit has potential health-promoting properties due to the presence of multitude bioactive compounds. Ongoing cell culture and animal studies in our lab using limonoids and flavonoids have provided strong evidence of their protective properties for preventing chronic diseases. Studies related to D-glucarate, a natural, nontoxic bioactive compound found in grapefruit, has not been explored. One of the derivatives, such as D-glucaro-1,4-lactone, is reported to be a potent ß-glucuronidase inhibitor. With the inhibition of ß-glucuronidase enzyme, glucuronidation will be favored. Glucuronidation is a conjugation process through which potentially carcinogenic environmental toxins can be neutralized. In this context, quantification of glucarate using HPLC was developed. Samples from grapefruits were prepared by heating fruit extract with distilled water. Further, the extract was homogenized and centrifuged. The supernatant was treated with petroleum ether to remove non-polar substances. Then the extract was subject to ion exchange chromatography. Fractions were collected and analyzed by analytical HPLC for the quantification of D-glucarate content and its lactone. This project was supported by the USDA-CSREES grant for Designing Foods for Health through the Vegetable and Fruit Improvement Center.