Non-steroidal antiphlogistics and COX-2 inhibitors routinely cause sodium retention and a blood pressure increase by about 5 mmHg, a decrease in renal function (by about 10 ml/min) and in 1-2% an acute renal failure. Prevention is possible by short-term, low-dose application, avoidance of dehydration, controlling serum creatinine levels 1 week after start of treatment in high-risk groups. Aminoglycosides cause acute renal failure in 10-20% which can be prevented by once daily dosing, meticulous drug monitoring. Radio contrast media cause, mostly dependent on baseline renal function, in 0-50% a radiocontrast-induced nephropathy. This can be prohibited with hydration, low volume of contrast medium, and low- (or iso)osmolar contrast medium. New preparations of vancomycin go along with a greatly reduced rate of nephrotoxicity. Drug monitoring and avoidance of a combination therapy with aminoglycosides will help to reduce toxicity. Medication-induced acute interstitial nephritis is a relevant differential diagnosis in acute renal failure: stop implicated medication, consider steroid application!