Acute kidney injury, known as AKI, is surprisingly common, especially among people in hospital. It happens when the kidneys stop working properly, often because of a change in blood flow due to surgery or an infection. If the kidneys do not recover quickly, it can turn into a chronic condition. Therefore, physicians would like better ways to prevent, diagnose and treat AKI. In this animation, we explain how risk algorithms, research into biomarkers and new drugs offer hope to patients and physicians.