 During her second year , Geiling was retained by the FDA to research unusual deaths related to elixir sulfanilamide , a sulfonamide medicine . Kelsey assisted on this research project , which showed that the 107 deaths were caused by the use of diethylene glycol as a solvent . The next year , the United States Congress passed the Federal Food , Drug , and Cosmetic Act of 1938 . That same year she completed her studies and received a Ph.D. in pharmacology at the University of Chicago . Working with Geiling led to her interest in teratogens , drugs that cause congenital malformations . 
