Hepatic encephalopathy is a disease in which confusion, decreased consciousness and coma are caused by liver failure and is divided into prodromal, precoma, coma and coma phases. The patient’s condition also becomes more severe from the prodromal phase to the coma phase, and the duration of maintenance varies according to the patient’s constitution, so it is not possible to specify the duration of each phase. The first stage of hepatic encephalopathy can be characterized by significant changes in personality and behavior, and patients mainly exhibit mild mental abnormalities such as anxiety and euphoric agitation; the second stage can be characterized by aggravated confusion of thinking, mainly drowsiness, apathy, abnormal behavior, and slurred speech; the third stage can be characterized by significant confusion, dysgraphia, disorientation, and amnesia, and drowsiness but can be awakened; the fourth stage is characterized by coma cannot be awakened. Encephalopathy is often complicated by other symptoms of liver failure, such as jaundice, ascites, and swelling of the legs; in severe cases, the patient’s exhaled breath contains a moldy sweet odor. However, the exact duration of maintenance of each stage is individually variable and there is no clear time demarcation. In conclusion, treatment of hepatic encephalopathy requires elimination of the causative factors causing hepatic encephalopathy and removal of toxic substances from the intestinal tract, etc. Patients may get better after treatment, and in severe cases, liver transplantation is required for treatment.