Many articles have been published over the years chronicling the amazing discovery of warfarin by UW biochemist Karl Paul Link´22, MS´23, PhD´25. Not only is this compound a powerful rat poison, but it is also widely used as a blood thinner for treating cardiovascular disease. According to a February 2002 article published in The Biochemist, a London-based medical journal, warfarin was the eleventh-most prescribed drug in the United States in 1999. Link, who was a Wisconsin graduate and fiercely loyal to the school's cause, named his discovery after the Wisconsin Alumni Research Foundation (WARF), which had funded his work.

The discovery of warfarin was sparked by a mysterious illness that had claimed the lives of many cows in the northern prairie states of America and Canada in the early 1900s. Link observed that moldy sweet clover hay, which some local farmers were fond of feeding their cattle, contained a poisonous compound called “coumarin” that was killing the animals by causing hemorrhaging. After earning the gratitude of thousands of cattle farmers, Link assigned patent rights for his discovery to WARF, which then successfully promoted warfarin as a premier rat poison in 1948.

Scientists soon uncovered another use for this versatile compound. In 1951, the story of a man who had consumed large doses of warfarin — and survived — convinced clinical investigators that while deadly to mice and rats, warfarin could be safely consumed by humans. Soon, medical researchers began to explore the potential human healthcare possibilities of warfarin. This culminated in the first clinical study involving the compound in 1955. Providing relief to countless stroke victims worldwide, warfarin was instrumental in helping President Dwight D. Eisenhower recover from a potentially fatal heart attack in 1955.

While warfarin saved President Eisenhower's life, it may have killed former Soviet leader Josef Stalin. According to Stalin's Last Crime, a book by Russian historian Vladimir Naumov and Yale professor Jonathan Brent, the iron-fisted dictator may have died from either cerebral hemorrhaging or warfarin poisoning.