“The wine which you drink never heard of a grape, / But of tannin and coal tar is made; / And you could not be certain, except for their shape, / That the eggs by a chicken were laid.”

Harvey Washington Wiley, advocate of the Pure Food and Drugs Act of 1906, penned these darkly jaunty lines in 1899. At the time, things were grim in the realm of food and drug safety: Coffee was very likely to contain sawdust, brown sugar might be supplemented with ground insects, and milk’s shelf life was often extended with formaldehyde.

By the time the major pharmaceutical breakthroughs of the 1930s through the 1960s began—with the development of antibiotics, sulfonamides, antihistamines, and synthetic hormones and vitamins—regulation had come a long way. But this explosion of novel drugs brought unprecedented regulatory challenges.

As a new hire at the Food and Drug Administration in 1960, Frances Oldham Kelsey, PhD’38, MD’50, was assigned to review an application for thalidomide, a sedative often prescribed for morning sickness. By 1962 she would become a household name for blocking the approval of the drug in the United States and preventing an untold number of birth defects. In her long career as a pharmacological researcher and leader at the FDA, Kelsey shaped how new drugs were investigated and regulated in the United States.

Frances Oldham was born in British Columbia about two weeks before Canada entered World War I. Interested in science from a young age, she discovered pharmacology at McGill University.

In 1936 she came to the University of Chicago to pursue a PhD and work in the brand-new pharmacology department with Eugene M. K. Geiling, the department’s first professor and chair. Geiling’s offer letter made Kelsey uneasy, though. “It started out, ‘Dear Mr. Oldham,’ and here my conscience tweaked me a bit. I knew that men were the preferred commodity in those days,” Kelsey said.

But she accepted—adding “Miss” after her signature—and didn’t look back. She did her dissertation research on the posterior pituitary gland in armadillos (“not one of your common laboratory animals, I can assure you,” she said), received UChicago’s first doctorate in pharmacology, and gained experience with drug testing that informed her later work at the FDA.

While at UChicago she worked with the FDA to investigate the “Elixir of Sulfanilamide,” a cherry-flavored liquid form of the early antibiotic intended especially for children. Since sulfanilamide was not soluble in water or alcohol, the manufacturer dissolved it in diethylene glycol (commonly used in antifreeze and brake fluid). Animal and clinical trials weren’t required by law, so the elixir went straight to market.

After deaths were reported, the FDA removed the elixir from the market and, lacking the resources to carry out such tests itself, asked Geiling and his lab to determine what ingredients in the concoction were toxic. This case helped lead to the passage of the 1938 Food and Drug Act, which expanded the FDA’s regulatory power and required a drug’s sponsor to submit evidence of safety.

During WWII Geiling’s lab received government funding to screen possible antimalarial drugs, and Kelsey stayed on after her PhD to help, conducting animal trials and observing clinical trials at Statesville Prison in Joliet, Illinois, the very kind of experiments for which she would write informed consent policy at the FDA. She also conducted research showing how pregnant animals and their embryos process drugs—work that would later help Kelsey assess the danger of thalidomide.

She married a colleague, Ellis Kelsey, in 1943, and they worked side by side in Geiling’s lab until UChicago revived a policy after the war that prevented spouses from working in the same department. As a result, Kelsey attended medical school at UChicago, during which time she had two daughters, and then worked at the Journal of the American Medical Association.

In 1960, after a stint in South Dakota, the couple happily accepted job offers in Washington, DC—Ellis at the National Institutes of Health and Frances at the FDA.

The thalidomide file landed on Kelsey’s desk a month into her new job. She later speculated that her colleagues gave it to a rookie because they didn’t expect problems with a sleeping pill, let alone one that had been marketed in Europe since 1957. The application was submitted in September 1960 in hopes of an approval before the holidays—“apparently the season for sedatives and hypnotics,” Kelsey remarked.

But problems were clear right away. Kelsey’s colleagues, who reviewed the first two parts of the application—chemical analysis and animal trials—found discrepancies between original German studies and the English translations submitted to the FDA, as well as hints that the drug might not be absorbed as described. Kelsey, who was responsible for reviewing the clinical trials, found that many of the reports submitted were more testimonial than scientific in nature. She sent the application back to the drug company, demanding proof of its claims.

In the meantime, Kelsey began to learn of serious side effects of the medication that were being reported in Europe, including peripheral neuritis—a tingling of the arms and legs. She requested more evidence of safety, facing down aggressive pressure from the drug company.

“They wrote letters and they telephoned—as often as three times a week,” she later told Life magazine. “Most of the things they called me you couldn’t print.”

Then came reports of birth defects in Europe, including missing limbs and heart malformations, in children exposed to thalidomide in utero—alarming revelations, as the drug was often prescribed to treat morning sickness. Thalidomide was removed from the German market and clinical trials in the United States were discontinued. Kelsey and her team began an extensive process of tracking down all doses of the drug that had been distributed, preventing the scale of tragedy that had taken place in other countries.

The recall of thalidomide and a blockbuster Washington Post profile of Kelsey, published in July 1962, precipitated amendments to the 1938 Food and Drug Act that Congress had been debating for years. Among other things, the 1962 amendments required sponsors of new drugs to submit their plan for safe clinical trials before conducting them.

The Washington Post story sparked a media frenzy that made Kelsey the face of the FDA for decades to come. Many journalists painted her as calm, quiet, and persistent in her drive to save the world’s children—as much a motherly figure as a scientific one. Some even suggested that Kelsey wouldn’t have put two and two together about thalidomide had she not been a mother.

Though often depicted as meek, she clearly enjoyed using the media and public appearances to educate people, encouraging them not to fear medicine but to remain cautious.

But the public had undeniably grown more wary about new drugs and the safety of clinical trials. In the late 1960s Kelsey became responsible for drafting a new informed consent policy and overseeing clinical trials. Over the following decades, Kelsey’s team of inspectors traveled the country to enforce safety protocols, focusing on settings, such as prisons, in which consent was ambiguous and populations were most vulnerable.

In 2010, 50 years after Kelsey received the thalidomide file, the FDA created and presented her with the Dr. Frances O. Kelsey Award for Excellence and Courage in Protecting Public Health.

Her home country of Canada, where thalidomide had been approved, was late to recognize Kelsey. In 2015 she was appointed to the Order of Canada; the ceremony was held at her daughter’s home in London, Ontario, due to Kelsey’s declining health. The small group enjoyed tea and one of Kelsey’s favorite songs, “Good Night Irene.” Kelsey died later that day, at the age of 101.

In her 45 years at the FDA, Kelsey played a central role in transforming the system by which untested substances could be put on the market and in introducing a robust national oversight program, which—though not risk-free—had the power to hold industry players and researchers accountable.

As she told Glamour in October 1962, “We can’t make an omelet without breaking the eggs. Advances have to come, even though they carry problems. It’s nothing to get alarmed about. It is something we must keep watch over.”