What is hepatitis B?

The term "hepatitis" means inflammation (or swelling) of the liver. When the liver is inflamed, it can have a harder time doing some of its jobs. (See Understanding the Liver.)

A hepatitis virus is one that lives in liver cells and causes inflammation. Different hepatitis viruses have been given different names, such as A, B, and C.

Hepatitis B is caused by the hepatitis B virus. Most people who get hepatitis B as adults can get rid of the virus on their own. But others, especially children and some adults, can develop chronic (or lifelong) hepatitis B that can lead to liver damage, liver cancer, and death.