Hepatic encephalopathy is a disease of reversible impairment of brain function that occurs after acute and chronic liver failure and a substantial increase in blood ammonia in the portal circulation by portal shunts, and is commonly seen in advanced cirrhosis, advanced hepatocellular carcinoma, severe hepatitis, or portal hypertension. The main clinical manifestations of hepatic encephalopathy are impaired consciousness, behavioral disorders and coma, which seriously endanger people’s health and life. Due to the different underlying causes leading to hepatic encephalopathy, the predisposing factors and clinical manifestations are also different. There are usually changes in personality and behavior. Patients may develop jaundice, bleeding tendency, peculiar odor of exhaled breath and fluttering tremor, and liver function tests show severely impaired changes. As the disease progresses, some patients may develop serious complications such as hepatorenal syndrome, cerebral edema and damage to major organs such as the heart, kidneys and lungs, which can lead to severe symptoms such as hypokalemia, hematuria, respiratory failure and coma. Predisposing factors for hepatic encephalopathy include upper gastrointestinal bleeding, high-protein diet, massive potassium diuresis, ascites discharge, etc. They also include the use of various sedative drugs and anesthetics. Constipation, uremia, and infections are all causes of hepatic encephalopathy. In conclusion, the causes of hepatic encephalopathy are various and patients should pay more attention to them, and liver protection is the key to treatment.