Hepatitis has different classification methods, such as viral hepatitis, alcoholic hepatitis and drug-induced hepatitis. From the etiology, it cannot be said that hepatitis is contagious. For example, drug-induced hepatitis is mainly caused by drugs, so it is not contagious; Hepatitis A (a viral hepatitis) is contagious.

Generally speaking, infectious hepatitis refers to viral hepatitis, that is, hepatitis caused by viruses. Due to the different viruses infected, viral hepatitis can be divided into hepatitis A, hepatitis B, hepatitis C, hepatitis D and hepatitis E, among which hepatitis A and hepatitis B are common infectious hepatitis in China. For example, hepatitis A broke out around Shanghai 1988. Hepatitis is mainly caused by hepatitis A virus, which is mainly transmitted through feces. It is because the sewage containing hepatitis A virus is discharged into the water untreated and gathered in the clam, and Shanghai people like to eat the clam raw, which leads to infection; Hepatitis B is mainly mother-to-child transmission, blood transmission, sexual transmission, iatrogenic transmission and close contact transmission (for example, when skin and mucosa are damaged, it is transmitted through razors and toothbrushes).