The widespread observation of magnesium depletion in edematous malnutrition has been confirmed in Guatemalan children. The magnesium requirement during initial stages of therapy has been estimated as 2.7 mEq/kg per day. This may be achieved by adding 0.5% MgSO4.7H2O to a solution containing 15% dextromaltase and 1.5% KCl which is used to dilute whole milk; two parts milk and one part dilution mixture. The replacement of magnesium deficits was not essential for recovery from edematous malnutrition, however, the present evidence suggested that the rate of recovery was accelerated by approximately 2 weeks in those children who received the supplement.