A Canadian doctor who fought to keep a drug out of the United States that would have resulted in one of the worst medical disasters in history has passed away. She was 101.

Dr. Francis Kelsey has been hailed as a heroine for opposing thalidomide in the 1960s, which was a teratogenic drug that was meant to be a safe sedative for pregnant women but resulted in a huge epidemic of birth defects worldwide, as well as in her own country of Canada, according to a Globe and Mail report.

She was just this week given the insignia of the Member of the Order of Canada for her heroic deed in blocking thalidomide from going into the United States despite facing fierce opposition from the drug’s profit-seeking boosters.

She had to be visited at her home by Ontario’s Lieutenant-Governor Elizabeth Dowdeswell due to her declining health.

The drug was made by German firm Chemie Grunenthal and had been approved for use worldwide. But Kelsey, who was a novice medical examiner at the time and had been working for the U.S. Food and Drug Administration, wasn’t convinced of his safety and insisted on getting scientific evidence despite the drug company’s attempts to lobby on behalf of thalidomide to get it into the United States.

Officials at the Food and Drug Directorate in Ottawa, meanwhile, signed off on the drug without protesting, and Canada paid the price, with 100 babies born with extreme deformities, including missing limbs and organ damage, with many dying shortly after birth.

Kelsey has also been honored in the United States, with President John F. Kennedy giving her the Award for Distinguished Federal Civilian Service all the way back in 1962.