11 January 1922

Insulin was first used to treat diabetes in a human.

On 11 January 1922, Leonard Thompson, a 14-year-old boy with diabetes, who lay dying at the Toronto General Hospital, was given the first injection of insulin. However, the extract was so impure that Thompson suffered a severe allergic reaction, and further injections were cancelled.

Over the next 12 days, James Collip worked day and night to improve the ox-pancreas extract, and a second dose was injected on the 23 January. This was completely successful, not only in having no obvious side-effects, but in completely eliminating the glycosuria sign of diabetes.

Children dying from diabetic ketoacidosis were kept in large wards, often with 50 or more patients in a ward, mostly comatose. Grieving family members were often in attendance, awaiting the inevitable death. In one of medicine’s more dramatic moments Banting, Best, and Collip went from bed to bed, injecting an entire ward with the new purified extract. Before they had reached the last dying child, the first few were awakening from their coma, to the joyous exclamations of their families.

Insulin was discovered by Sir Frederick G Banting, Charles H Best and JJR Macleod at the University of Toronto in 1921 and it was subsequently purified by James B Collip.Before 1921, it was exceptional for people with Type 1 diabetes to live more than a year or two. One of the twentieth century’s greatest medical discoveries, it remains the only effective treatment for people with Type 1 diabetes today.