Acute renal insufficiency is often called "lower nephron nephrosis." Its recognition, its prognostic significance, and its therapy by conservative measures are receiving increasing clinical emphasis. The mortality rate in this complicated syndrome still remains unduly high. One method of therapy of anuric patients whose lives are in jeopardy because of fulminating uremia or critical potassium intoxication is use of an artificial kidney to "purify" the blood stream by means of extracorporeal dialysis.The author describes clinical (and laboratory) experience with ten such dialyzed patients, eight of whom presented the classical picture of acute renal insufficiency. Four died, one from unrecognized coronary occlusion, another from antecedent, overwhelming peritonitis. Two other patients with chronic kidney disorders received no benefit from dialysis and died of renal disease. Good biochemical and clinical response was brought about in six cases of lower nephron nephrosis. Presumably, these six patients would have died had they not been subjected to artificial dialysis.