It kills ants. Very dead. When I had them, I watched them for a few hours, They would sit there and suck on the spot until their butts got huge, then they'd trundle back home and give it to the wife and kids.
I found it at the local hardware, under "things that will poison you" next to "things that might explode" and "things that will remove a limb".
Still Remember mom putting the milk cap full of Terro right behind the Pop-Tarts.