Albumin turnover was measured in a whole body counter in six normal infants and 12 infants with iron deficiency anemia following the intravenous injection of 0.12 microcuries of iodinated I 131 serum albumin. Seven of the 12 patients had a rapid turnover (half-times less than ten days) which indicated significant exudative enteropathy. Treatment with iron dextran injection (100 mg parenterally) had no effect on the albumin turnover. Feeding evaporated milk instead of fresh cow's milk was followed by a lengthening of albumin turnover half-times in four out of five patients. Replacement of milk by a soybean substitute was always followed by a return to normal values. These observations suggest that there is a spectrum of effects of fresh cow's milk on the intestinal tract which are not due to iron deficiency.