Background: Contrast nephropathy (CN) remains a common complication of radiographic procedures and an important cause of hospital-acquired acute renal failure, which contributes to morbidity and mortality during hospitalization, as well as costs of health care. Many previous strategies to prevent CN (such as N-acetylcysteine, aminophylline, fenoldopam, hemofiltration) have been unsuccessful or at least controversial. Only hydration with saline is uniformly accepted and used in clinical practice as cornerstone for the prevention of CN. But the optimal preventive strategy for CN is not known. According to a recent study, periprocedural hydration with sodium bicarbonate might be even more effective than hydration with sodium chloride for prophylaxis of CN. Such a preventive hydration with sodium bicarbonate should be compared with the gold standard of hydration with saline (24-h hydration period). This has not been evaluated so far. Given its high oral bioavailability, sodium bicarbonate could be administered even orally instead of a prolonged infusion. An effective short-term regimen would be highly attractive in clinical practice including outpatient procedures.