In 1948, Warfarin was introduced as a pesticide against rats and mice. Warfarin (a.k.a. Coumadin) is an anticoagulant used in the prevention of thrombosis and thromboembolism.

Warfarin was developed by University of Wisconsin biochemist Karl Link. The name “warfarin” stems from the acronym WARF, for Wisconsin Alumni Research Foundation + the ending -arin indicating its link with coumarin. Although warfarin was developed by Link, the WARF financially supported the research and was assigned the patent.[