Michael reveals how pain-free surgery became possible because of self-experimenters like Humphrey Davy and Sigmund Freud. He also experiences for himself some of what they went through and watches a modern day self experimenter in action.

Michael meets researchers infecting themselves with hookworm in a novel bid to control allergies. He tells the dramatic and sometimes tragic stories of the scientists who developed cures for some of history's greatest killers - rabies, typhoid and polio.

Michael shows how the links between food and health were first established by men like Dr Joseph Goldberger. He famously ate a dying patient's excrement and by doing so changed forever what goes into our food.

Michael shows how, by infecting themselves with syphilis, yellow fever and cholera, doctors transformed our understanding of disease. He ends the series with Dr Barry Marshall who recently won a Nobel Prize thanks to a particularly courageous act of self-experimenting.