The binding properties of raw vegetable fiber towards bivalent cations suggested the prescription of bran as a dietary supplement to limit intestinal calcium absorption in hypercalciuric patients. A group of 18 patients with a specific diagnosis of absorptive hypercalciuria received a dietary supplement of 14gm. wheat bran at the 2 principal meals for 90 days. A complete assessment of mineral metabolism was performed after 45 and 90 days. Mean basal calciuria was 357mg. per 24hours and a significant decrease was noted after 45 days (245mg. per 24hours) and 90 days (240mg. per 24hours), with a p value of less than 0.01. Urinary oxalate did not vary significantly (0.34 to 0.38 to 0.31mMol. per 24hours) and neither did phosphate levels (1,020 to 900 to 893mg. per 24hours). A slight and pathologically insignificant decrease was noted in serum iron and urinary magnesium; this fact could be considered a side effect owing to the nonselective binding properties of fiber. Therefore, the positive results achieved confirm the effective action of wheat bran in the treatment of correctly diagnosed absorptive hypercalciuria. (J. Urol., 142: 1018–1020, 1989)