Metabolic alterations as a result of bowel being employed in the urinary tract are well documented. To investigate this phenomenon in the continent ileal reservoir urinary diversion, 106 patients who had undergone Kock pouch surgery were followed in a prospective study at the University of Southern California between 1985 and 1987. Serum chemistries and urine osmolality determinations were performed approximately every three months for a year. Mean patient values for each time period were then compiled and compared with the norms and with the preoperative values. The mean serum electrolyte values were found to be within normal limits during all follow-up periods. Fourteen patients were identified, however, as having values falling intermittently outside of the normal range. These patients were investigated and found to be abnormal during episodes of acute renal failure usually secondary to dehydration or obstruction at which time they usually became acidotic and occasionally hyperchloremic. These problems disappeared when the renal failure was corrected. This study corroborated our previously reported findings that hyperchloremic acidosis or other metabolic alterations requiring replacement therapy do not routinely occur in this population.