The paper describes a case of severe preranal acute renal failure that was induced by the uncontrolled long-term use of furosemide and that was reversible after infusion therapy. Another case is a female patient with anorexia nervosa and end-stage uremia progressing to chronic tubulointerstitial nephritis. Some problems of the pathogenesis of kidney injury and its diagnostic difficulties in anorexia nervosa and diuretic abuse are discussed.