need to find the name of a rat poison that comes in the shape of a bar , it dehydrates after eaten?

Question

found a nest of rats in house,
there is a bar or log (dark brown) when rats eat it , they get dehydrated & when they drink water it kills them

Answer 1

yes it is warfrin it also comes in powder and wafer form, any general store should carry this.

Answer 2

Not sure of the spelling, but it's called warfin. It is also sometimes green.