Acute liver failure (ALF) is defined as the sudden onset of severe liver dysfunction in patients who did not previously have chronic liver disease. It can be categorized into fulminant, acute, subacute, and protracted ALF based on the time interval between liver dysfunction and encephalopathy. The most common causes in Germany are viral hepatitis and medication toxicity. Other rare causes include mushroom poisoning, Wilson's disease, and the Budd-Chiari syndrome. The clinical presentation of ALF is characterized by severe liver insufficiency (with jaundice and coagulation disorders) and encephalopathy. The prognosis is poor, especially if the encephalopathy develops rapidly. Prognostic factors include the underlying etiology, patient age, and the dynamics of the disease progression. Treatment focuses on stabilizing vital functions, managing complications, and preventing further liver damage. Therapeutic options include specific treatments for paracetamol overdose, mushroom poisoning, and pregnancy-related liver failure. New therapeutic approaches, such as nucleoside analog therapy and liver replacement procedures, are being explored but have not yet shown significant efficacy.Acute liver failure (ALF) is defined as the sudden onset of severe liver dysfunction in patients who did not previously have chronic liver disease. It can be categorized into fulminant, acute, subacute, and protracted ALF based on the time interval between liver dysfunction and encephalopathy. The most common causes in Germany are viral hepatitis and medication toxicity. Other rare causes include mushroom poisoning, Wilson's disease, and the Budd-Chiari syndrome. The clinical presentation of ALF is characterized by severe liver insufficiency (with jaundice and coagulation disorders) and encephalopathy. The prognosis is poor, especially if the encephalopathy develops rapidly. Prognostic factors include the underlying etiology, patient age, and the dynamics of the disease progression. Treatment focuses on stabilizing vital functions, managing complications, and preventing further liver damage. Therapeutic options include specific treatments for paracetamol overdose, mushroom poisoning, and pregnancy-related liver failure. New therapeutic approaches, such as nucleoside analog therapy and liver replacement procedures, are being explored but have not yet shown significant efficacy.