ABSTRACT
Warfarin, which was introduced to the market in the late 1940s, was the rst of a series of anticoagulant rodenticides (ARs) related in structure to dicoumarol (Figure 11.1; Buckle and Smith 1994; Meehan 1986). All of them are toxic because they act as anticoagulants, extending the clotting time of blood and thus causing hemorrhaging. The anticoagulant properties of naturally occurring dicoumarol were discovered in the United States early in the 20th century, when it was found to be the causal agent in cases of fatal hemorrhaging of cattle fed with spoiled clover. Subsequently, it was discovered that dicoumarol and rodenticides related to it have anticoagulant action because they act as vitamin K antagonists.
