Insulin injection aids diabetic patient In Toronto, Canada, 14-year-old boy Leonard Thompson becomes the first person to receive insulin as treatment for diabetes. Diabetes has been recognized as a distinct medical condition for more than 3,000 years, but its exact cause was a mystery until the 1920s. Canadians Frederick Banting and Charles Best extracted insulin from the pancreas of cattle from slaughterhouses and began treating Leonard Thompson. The teenager improved dramatically. By 1923, insulin had become widely available, saving countless lives around the world. __
