SummaryThe effects of the creation of an ileac stoma on the loss of nitrogen, sodium, potassium and calcium have been studied mostly among patients who had ulcerative colitis. In such patients the loss of nitrogen is reduced by creation of the stoma; the average daily loss of 1 to 2 Gm. from an established ileac stoma is not significant for patients on a normal diet. The loss of potassium is checked; the postoperative loss usually is insignificant. The loss of sodium is increased by the performance of ileostomy, and may be severe in the immediate postoperative period. For those concerned in the treatment of such patients, the establishment of an ileac stoma switches the electrolyte problem from one involving potassium to one involving sodium, for the ileac stoma halts the loss of potassium, but creates a sodium imbalance. Up to 300 mEq. of sodium can be lost per liter of exudate from a recently established stoma, and 150 mEq. per liter is lost from a fully established stoma. The amount of sodium required for restoration may be calculated from the volume of the output on this average. The administration of cortisone reduces the total loss of fluids and sodium, without increasing the total output of potassium.From the established ileac stoma calcium is excreted at a little more than 1 Gm. daily by patients on a normal average diet; nevertheless, positive calcium balance appears to be maintained.