Hepatitis A, hepatitis B, hepatitis C and hepatitis E are characterized by different pathogenic microorganisms, different routes of disease transmission, and different rates of disease progression and prognosis. Hepatitis A, B, C, and E have different pathogenic microorganisms. Hepatitis A is caused by hepatitis A virus (HAV), which is an RNA virus; hepatitis B is caused by hepatitis B virus (HBV), which is a DNA virus; hepatitis C is caused by hepatitis C virus (HCV), which is an RNA virus; and hepatitis E is caused by hepatitis E virus (HEV), which is an RNA virus. Hepatitis A, hepatitis B, hepatitis C and hepatitis E have different transmission routes, disease progression and prognosis. Hepatitis A and hepatitis E are generally transmitted through the fecal-oral route, and patients usually show symptoms of acute hepatitis, and the prognosis is generally good. Hepatitis B and C are mainly transmitted through blood, mother-to-child transmission and sexual contact, and patients may show symptoms of acute hepatitis, and the disease may migrate to chronic hepatitis, and the prognosis of patients with mild disease is good, while the prognosis of patients with severe disease is poor.