Overcorrection of hyponatremia is a medical emergency. Excessive correction usually results from the unexpected emergence of a water diuresis after resolution of the cause of water retention. The concurrent administration of desmopressin and 5% dextrose in water can be given to cautiously re-lower the serum sodium concentration when therapeutic limits have been exceeded. Nephrologists should be equally aggressive in correcting hyponatremia and in un-correcting it when their patients get too much of a good thing.