Chronic plus acute liver failure refers to the clinical syndrome of liver failure due to acute liver injury on top of pre-existing chronic liver disease, manifested by symptoms such as jaundice, coagulation disorders, concurrent ascites and hepatic irritability. The clinical subtypes of ACLF include: 1. Type 1 ACLF: good liver function compensation despite chronic liver disease before the development of liver failure; 2. Type 2 ACLF: decompensated cirrhosis already exists before the development of liver failure. Among the causes of liver failure, alcoholic hepatitis is the main cause in Western countries, and hepatitis B virus or hepatitis C virus infection is the main cause in Asia. The proportion of alcoholic and drug-related factors has increased significantly in the last 3 years. The causes of HBV-induced slow-accelerated liver failure include: interruption or reduction of nucleotide drugs, HBV mutation and irregular use of antiviral drugs accounting for 13.2%; exertion and alcohol consumption accounting for 10.8% and 3.5% respectively; hepatotoxic drugs accounting for 8.1%; and abdominal infection accounting for 1.4%. Acute causes of ACLF: 1. Infectious factors: (1) hepatophilic or non-hepatophilic virus infection; (2) hepatitis B (dominant or recessive) or hepatitis C reactivation; (3) other infectious factors affecting the liver. 2. Non-infectious factors: (1) alcohol: history of alcohol consumption within 4 weeks; (2) hepatotoxic drugs, herbal medicines; (3) autoimmune hepatitis or Wilson’s disease episodes; (4) variceal bleeding (no consensus); (5) surgical procedures. 3. unknown hepatotoxic factors.