Hepatitis C is a blood-borne infectious disease that is caused by Hepatitis C virus (HCV) infecting the liver. The infection can cause liver inflammation (hepatitis) that is often asymptomatic, but ensuing chronic hepatitis can result later in cirrhosis (fibrotic scarring of the liver) and liver cancer.

The hepatitis C virus (HCV) is spread by blood-to-blood contact with an infected person's blood. No vaccine against hepatitis C is available. The symptoms of infection can be medically managed, and a proportion of patients can be cleared of the virus by a long course of anti-viral medicines. Although early medical intervention is helpful, people with HCV infection often experience mild symptoms, and consequently do not seek treatment. An estimated 150-200 million people worldwide are infected with hepatitis C.

The hepatitis C virus is one of six known hepatitis viruses: A, B, C, D, E, G.