SummaryA case of intoxication with potassium ferricyanide in a 18 years patient is described. The most spectacular effect of this intoxication was a massive renal glucosuria; slight azotemia and transient albuminuria were also observed.Studies of renal clearances and glucosuria have shown, in an initial stage, profound changes in all tubular functions and complete lack of glucose reabsorption. A progressive functional amelioration was noted during later studies. Our results suggest a marked inequality in the epithelial regeneration of the different nephrons, some being overactive. This behaviour is similar to that of the patients with renal diabetes who belong to the second type of this disease (type B characterized by a poor correlation between tubular and glomerular functions of the nephrons).Renal glucosuria is readily produced in the animal by the administration of adequate amounts of potassium ferricyanide.