Too often in the uremic patient the therapeutic sequence is as follows. Overhydration leads to dilutional hyponatremia, which is interpreted as salt loss, despite anuria. Sodium is administered, and the consequent increase of extracellular volume precipitates pulmonary edema. Digitalis is prescribed. The usual dose is excessive because of renal failure, but the pulmonary edema of renal origin does not respond. Digitalis intoxication is masked by hyperkalemia. The digitalis excess and hyperkalemia increase and finally the patient is referred for dialysis. Even cautious lowering of the potassium at this point may cause fatal arrhythmia.