Metabolic derangements are a frequent accompaniment of bowel interpositions in urologic surgery. The incidence of metabolic complications secondary to these procedures is a function of the absorptive capacity of the bowel segment used, the surface area of the bowel in contact with the urine, the length of time the urine is in contact with the bowel, and the patient's inherent ability to handle an added electrolyte insult. Each of these factors must be considered when contemplating bowel interposition in the urinary tract.