The nonphysiological high chloride content of 0.9 % saline causes hyperchloremic acidosis and rapidly reduces renal perfusion in healthy volunteers-negative affects not seen with balanced crystalloids with low chloride content. Evidence from recently published studies strongly suggests that 0.9 % saline negatively effects outcome in surgical and critically ill patients. Major complications are the increased incidence of acute kidney injury and need for renal replacement therapy, as well as higher postoperative in-hospital mortality. Although implemented as the gold standard in many clinical guidelines, there are currently no data supporting the use of 0.9 % saline instead of modern balanced crystalloids. This is also and even particularly true for patients with hypokalemia and acute or chronic kidney injury. In-house training is an effective tool for sustainably raising the awareness of this issue among nursing and medical staff, and identifying alternative strategies to the use of NaCl 0.9 % in clinical practice.