Kelsey was first introduced to the dangers of mass marketed unsafe pharmaceuticals in 1937, when the FDA enlisted Geiling to solve the mystery of Elixir of Sulfanilamide. Sulfanilamide effectively combated infections, but it came in a large and bitter pill that needed to be taken in large dosages. To make the drug more appealing, especially to children, manufacturers added it to a solvent with artificial raspberry flavor.Kelsey went to medical school and joined the FDA in 1960. Read her story, and how her research on Thalidomide saved American babies, at Smithsonian.
The problem was that the solvent they chose was diethylene glycol—commonly known as antifreeze. Between September and October, the drug killed 107 people.
Geiling and his lab of graduate students, including Kelsey, set out to determine what exactly in the elixir was killing people: the solvent, the flavor or the sulfanilamide. Through a series of animal studies—which at the time were not required by federal law for a drug to go to market—Geiling and his lab were able to determine that it was the diethylene glycol that was the cause of death.