Hepatitis is a collective name for liver inflammation caused by various reasons, which can be categorized into alcoholic hepatitis, drug hepatitis, viral hepatitis, autoimmune hepatitis and steatohepatitis according to different pathogenic factors. 1. Alcoholic hepatitis: after ethanol enters the body, it is first converted into acetaldehyde and then into acetic acid. If the conversion of acetaldehyde to acetic acid is impaired or incomplete, the accumulation of acetaldehyde can occur. Acetaldehyde is directly toxic to the liver and can cause liver cell degeneration and necrosis. At the same time, under the stimulation of ethanol can also produce inflammatory factors, etc., aggravate liver injury, and eventually form alcoholic hepatitis. 2. Pharmacological hepatitis: direct or indirect hepatotoxicity of drugs and their metabolites may lead to cellular hypoxia, lipid peroxidation and immune dysfunction, etc., which will eventually lead to the occurrence of hepatitis. 3. Viral hepatitis: common hepatitis A, hepatitis B, hepatitis C and hepatitis E, etc. After the virus enters into the human body, it activates the immune system of the human body, and the immune system attacks the infected hepatocytes, which can cause damage to the hepatocytes, and ultimately lead to the occurrence of hepatitis. 4. Autoimmune hepatitis: immune disorders caused by various reasons lead to immune attacks against liver cells, which eventually lead to the occurrence of hepatitis. 5. Steatohepatitis: it may be due to obesity, drugs, metabolism and other factors, resulting in lipid metabolism disorders, excessive lipid deposition in the liver, ultimately leading to the occurrence of hepatitis. Patients suspected of hepatitis are advised to consult a doctor in time to clarify the cause as well as the type of hepatitis and then follow the doctor’s instructions for active treatment.