Warfarin - This article is about the drug with the brandname Coumadin. For the anticoagulant rodenticide poisons often called "coumarins" or "coumadins", see 4-hydroxycoumarins.

4-hydroxycoumarins

Warning label on a tube of rat poison laid on a dike of the Scheldtriver in Steendorp, Belgium. The tube contains bromadiolone, a second-generation ("super-warfarin") anticoagulant.

To this day, the so-called "coumarins" (4-hydroxycoumarin derivatives) are used asrodenticides for controlling rats and mice in residential, industrial, and agricultural areas. Warfarin is both odorless and tasteless, and is effective when mixed with food bait, because therodents will return to the bait and continue to feed over a period of days until a lethal dose is accumulated (considered to be 1 mg/kg/day over about six days). It may also be mixed with talcand used as a tracking powder, which accumulates on the animal's skin and fur, and is subsequently consumed during grooming. The LD50 is 50–500 mg/kg. The IDLH value is 100 mg/m³ (warfarin; various species).[55]