Borax has a low toxicity rate for humans and pets, but it's very fatal to ants once they consume it. ... And gradually, this feeding and sharing process will kill off the queen and her entire colony of ants, taking anywhere from a couple of days to a couple of weeks, depending on the size of the colony.

What is the fastest way to kill an ant colony?

Boiling water. If you notice ant holes near your home, pour boiling water into them. This will effectively and immediately kill many of the ants inside. Ant hills may appear small, but the ant colonies underneath them are wide.

What will kill an ant colony?

Borax. Make a colony-killing bait by blending equal parts Borax and corn syrup. Smear on a small piece of cardboard or index card. Ants love corn syrup, and when they eat it, the Borax kills them.