From religious ceremony to myths and horror movies, blood is the most potent of human symbols.

Yet aside from its visceral and symbolic aspects, blood keeps us alive. It is the highway that takes oxygen and other vital substances around the body. It can be donated or sold, frozen or transfused—and it can carry killer diseases.

This episode of Kill or Cure examines the history of blood. From the discovery of blood typing (and the strange paternity suit of Charlie Chaplin) to the medical breakthroughs of transfusions, and modern ‘bloodless’ operations for people who refuse transfusions; to the ancient but still used practices of applying leeches and bloodletting.

Whether it is being sought by a hungry vampire, or used in a modern hospital, blood flows in a rich red torrent through both medical and mythical history.