The etiology of acute renal failure is quite complex, in contradistinction to the monotonous appearance of the corresponding renal pathomorphology (tubular necrosis, intracapillary coagulation). A basic prerequisite for the successful prevention of acute renal failure is the knowledge of the responsible atiopathogenetic factors and their early recognition. Once kidney damage has occurred, therapeutic measures shift to concentrate on the symptomatic treatment of renal failure and the prevention of accompanying complications such as a hemorrhagic tendency, susceptibility to infections, hyperkalemia, hyperhydration, catabolism etc. In addition to the proper choice of the detoxification procedure (hemodialysis, hemofiltration, peritoneal dialysis, continuous a.v. hemofiltration) precise fluid and electrolyte balance, optimal nutrition, and the adjustment of drug dosages to the degree of renal insufficiency all play an important rule. The therapeutic principles and the differential therapy of the various detoxification procedures are discussed on the basis of concrete recommendations.