CBC4Kids: History of Inventions, a timeline from Pottery to Computers.

Insulin

1921

Thanks to Glen R. for this suggestion.

Canadian Dr. Frederick Banting, with Charles Best and J.J.R. Macleod, isolated insulin, the substance secreted by the pancreas that allows the body to metabolize sugars.

Since then, insulin has allowed millions of diabetics around the world to lead healthy, active lives.