Because it would require a complex observation with steps and time involved, I'm going to go away from my gut instinct, saying rats first, and say man noticed it in himself first. read more
Warfarin was first used as a rat poison or rodenticide because it was considered to be too potent to be safely used in humans, but after a blood test was developed to measure and adjust its blood-thinning effects, warfarin has become the most widely used oral anticoagulant in the United States. read more
At first, warfarin was considered too toxic for human use. It was marketed as a rodenticide, and became a popular rat poison. In the 1951, a navy recruit took a large dose of warfarin to attempt suicide. read more