Abstract: Acute-on-chronic liver failure (ACLF) is a syndrome characterized by acute decompensation
of liver function in the background of a pre-existing chronic liver diseases, which often associated with
multiorgan failures and has a high short-term mortality. Different definitions of ACLF in different region
based on different populations lead to inconsistent diagnostic criteria. Chronic viral hepatitis, active
alcoholism, relapse of chronic viral hepatitis, drug induced liver injury or sepsis are the most common
reported precipitating events, but there are still up to 40%～50% patients with ACLF have no identifiable
trigger. Child-Turcotte-Pugh (CTP) score and model for end-stage of liver disease (MELD) score are
commonly used for evaluating the prognosis of patients with ACLF. Recently, intensive care scores related
to organ function are receiving increasing attention and accumulating evidences have demonstrated that
modified scores based on them could evaluate the prognosis effectively. Some biological markers like
cytokines interleukin-6, interleukin-17 and soluble mannose receptor (sMR) are closely associated with
the prognosis of ACLF. The course of ACLF is dynamic and the pathophysiological mechanisms of these
syndromes are quite complicated. The formation and the development of ACLF may be related to the immune
dysfunction and excessive inflammation response. There is no specific treatment for the management of
ACLF currently, general treatment are similar to severe cirrhosis. Some patients get complete recovery after
removing predisposing event and receiving effective treatment, but some cases have a poor prognosis. Liver
transplantation is therapeutic. Bio-artificial liver support systems and granulocyte-colony stimulating factors
are in the horizon of medical care of patients with ACLF. Therapies focus on the cytokines in the process of
inflammation and immunoregulation may be new directions in the future, however, data are too premature to
implement as standard care.