Patients with a reduced length of small intestine ending in a stoma experience loss of water and sodium, even when they take nothing by mouth. After food or drink, the loss from the stoma increases. Secretors are patients who lose more from the stoma than they take in by mouth. Absorbers are those whose output is less than their intake. In both groups, the sodium concentration of the effluent is about 90 mmol/L. The secretors are in constant negative sodium balance of up to 400 mmol/day and can only maintain balance with self-administered parenteral water and sodium. The absorbers may lose 200 mmol of sodium daily and need to take an oral sodium supplement to maintain balance. The optimal oral replacement solution has a concentration of at least 90 mmol/L of sodium. Lower sodium concentrations, or drinking water without sodium, lead to increased sodium losses and negative balance. The role of glucose, glucose polymers, or bicarbonate in promoting sodium absorption in the short bowel is unclear. Potassium losses from a small intestinal stoma are small. A modified glucose electrolyte solution, without potassium or bicarbonate and with a sodium concentration of 90 to 120 mmol/L, is appropriate for patients with an intestinal stomal output of 1 to 2 L daily. Once the output rises above 2 L daily, it is difficult to maintain sodium balance with an oral supplement.