What Is Hepatitis?

Hepatitis (pronounced: hep-uh-TIE-tiss) is an inflammation of the liver. The liver, in the right side of the abdomen, is an important organ that processes nutrients, metabolizes medicines, and helps clear toxins from the body.

Most cases of hepatitis are caused by a virus. The three most common hepatitis viruses are hepatitis A, hepatitis B, and hepatitis C. (Hepatitis viruses D and E are rare in the United States.)

Hepatitis that's not caused by a virus can happen from things such as:

• a bacterial infection
• liver injury caused by a toxin (poison)
• liver damage caused by interruption of the organ's normal blood supply
• liver damage caused by interruption of the flow of bile through the liver
• abdominal trauma in the area of the liver
• an attack on the liver by the body's own immune system (called autoimmune hepatitis)
• a problem with the liver itself

What Is Hepatitis A?

Hepatitis A is contagious, and usually spreads through food, drink, or objects contaminated by feces (poop) containing the hepatitis A virus. The hepatitis A vaccine has made the infection less common in the United States and other developed countries.

This virus can cause severe symptoms, but unlike some other hepatitis viruses, it rarely leads to long-lasting liver damage. People recover from hepatitis A have immunity to the virus and won't get it again.

Read more about hepatitis A.

What Is Hepatitis B?

Hepatitis B is a more serious infection. It can lead to cirrhosis (permanent scarring) of the liver, liver failure, or liver cancer, causing severe illness and even death.

The hepatitis B virus spreads from person to person through blood or other body fluids. In the United States, this most commonly happens through unprotected sex with someone who's infected or from injecting drugs with shared needles that aren't sterilized. It also can pass from an infected mother to her unborn baby.

The hepatitis B vaccine is approved for people of all ages to prevent HBV infection.

Read more about hepatitis B.

What Is Hepatitis C?

The hepatitis C virus spreads from person to person through blood or other body fluids, and can lead to cirrhosis or liver cancer. The most common way people become infected is by sharing drug equipment such as needles and straws. People also can get hepatitis C from unprotected sex with an infected partner. And it can pass from an infected mother to her unborn baby.

Hepatitis C is the most serious type of hepatitis. It's now one of the most common reasons for liver transplants in adults. Scientists have been trying for decades to develop a hepatitis C vaccine, so far without success. Fortunately, medicines can now treat people with hepatitis C and cure them in most cases.

Read more about hepatitis C.