Introduction

Hepatitis is inflammation of the liver from any cause.

Hepatitis commonly results from a virus, particularly one of the five hepatitis viruses--A, B, C, D, or E (a sixth category called hepatitis virus G had been created but has since been retracted). Less commonly, hepatitis results from other viral infections, such as infectious mononucleosis, yellow fever, or cytomegalovirus infection. The major nonviral causes of hepatitis are excessive alcohol intake and use of certain drugs, such as isoniazid (used to treat tuberculosis).

Hepatitis can be acute (short-lived) or chronic (lasting at least 6 months). It is common throughout the world.

See the table The Hepatitis Viruses.