A commercially available wheat bran preparation has been given to six infants between the ages of 6 and 16 months suffering from constipation not due to metabolic or anatomic causes. In all infants, normal bowel movements reappeared after a month of a diet containing bran. After a month on this diet, we observed the following: a decrease in blood levels of calcium, phosphate, and trace elements; an increase in fecal excretion of biliary salts and cholesterol; and an appearance of predominantly proteolytic fecal flora over the saccharolitic flora. These findings, especially the first one, indicate that bran preparations should be used in infancy with extreme caution because of possible side effect on the patient's nutritional status and growth. If bran is used, blood levels of minerals should be repeatedly checked in order to prevent the appearance of vitamin D-dependent rickets and the depletion of trace elements.