Urea kinetics were measured in a child with congenital absence of the
colon on days 15, 19, and 23 of age. Urea salvage was 5% of urea produ
ction in the first study, increasing to 79% by the third. This provide
s evidence that the colonic microflora play a more active part in urea
salvage than the mucosa and that the establishment of an active lower
ileal microflora takes over some of the metabolic functions of the in
tact colon.