I have read cream of wheat works, although I haven't tried it. They take it back to the colony and eat the stuff, it expands inside them and kills them. Just set a pile of it on a plate or newspaper on the floor where the ants are the worst, they will find it.

__________________
You know the difference between involvement and commitment don't you? In a meal of bacon and eggs, the chicken is involved, the pig is committed. -Pratt