Be careful about using the Hartz and other DIY stuff from retail stores.
I almost killed my cat with that stuff. Vet says he's treated many sick animals that had been treated with HARTZ. It is a very harsh insecticide.
Even though you put it on the coat or skin, it does enter the bloodstream.
The vets use the good stuff (that wont cause kidney/liver damage) and it's worth the money.
