Objective To explore links between genetic responsiveness to the bitter taste of 6-7i-propylthiouracil (PROP) and self-reported preferences for vegetables and fruit of female breast care patients.Methods PROP tasting was defined by detection thresholds and by perceived bitterness and hedonic ratings for PROP solutions. Nontasters, medium tasters, and supertasters were identified by their PROP thresholds and by the ratio of perceived bitterness of PROP to the perceived saltiness of sodium chloride solutions. Subjects rated preferences for vegetables and fruit using 9-point category scales.Subjects/setting A clinical sample of 170 patients with newly diagnosed breast cancer and 156 cancer-free control subjects were recruited from the University of Michigan Breast Care Center.Statistical analyses Principal components factor analysis, one-way analyses of variance, and Pearson correlations and χ 2 tests were used to analyze taste and food preference data.Results Genetic responsiveness to PROP was associated with lower acceptance of cruciferous and selected green and raw vegetables (P<.05). Women who reported disliking such foods were medium tasters or supertasters of PROP. Preference ratings for fruit were unrelated to PROP taster status.Applications/conclusions Women who are PROP tasters may be less likely to comply with dietary strategies for cancer prevention that emphasize consumption of cruciferous vegetables and bitter salad greens. Alternatively, PROP-sensitive women may seek to reduce bitter taste by adding fat, sugar, or salt. J Am Diet Assoc. 2000; 100:191-197.