When Professor Karl-Paul Link of University of Wisconsin was helping ranchers to solve the mystery behind dying cattle back in 1933, he would have never imagined that his discovery can one day lead to the development of a rat poison, as well as a medication that saved the life of a U.S. president.
Link found that coumarin, a compound he extracted from sweet clover hays, can prevent fibrinogen in blood from forming form clots by interfering with vitamin K, failing the process of blood clots forming. This unique property caused cows, which fed on sweet clover, to die from unstoppable bleeding.
Later to solve the rodent problem in a hospital he stayed in, Link thought of a use for coumarin as rat poison. He then patented the compound and rename it "warfarin", as an acknowledgment of his funding source the Wisconsin Alumni Research Foundation (WARF).
Medical researchers began to experiment with warfarin on stroke and arrhythmia patients because they knew that strokes were frequently caused by clots in the brain and the right dosage of warfarin should be able to decrease the formation of clots thus the frequency of stroke.
Warfarin did not become a household name until 1955 when President Dwight D. Eisenhower had a heart attack while on vacation at his in-laws' house in Denver. Eisenhower's long-term treatment included Warfarin 35 mg per week. Since then, it has been one of the most widely prescribed drugs in the United States.
Source: Nature Video via Youtube