When consumed by livestock it inhibits vitamin K production. Vitamin K is necessary in the body to activate prothrombin. When tissue is damaged, thromboplastin is released and converts prothronin to thrombin. Thrombin alters the solubility of fibrinogen in blood and causes it to clot and seal the tissue damage. Dicoumarol prevents this process .
Warfarin is a synthetic toxicant derived from coumarol.
It is used in rat, gopher, and ground squirrel poisons and also acts as a vitamin K inhibitor to block the blood clotting process and provoke hemorrhaging. It is toxic to livestock that may accidently consume it in its pelleted form and to dogs that consume poisoned squirrels,etc. Its coumarin content gives it a distinctive sweet odor similar to vanilla. Its use as hay was widespread in the 1920s. Use of the forage is less common now and low- melilotoside varieties are available.