I second this if you don't want to do the water suspension trick -- the diatoms are the shells of tiny (sea if I remember from biology) creatures, so they are microscopic and made out of silica. This powder (to us) is like walking through shards of glass (to ants), and they breathe it and track it back to the nest. It cuts them up and also makes them not come back.

It's not poison for humans, pets, or anything mammalian. It'll help with insect pests on plants, and things that walk around in the house. And the cleanup requires a dust broom and pan, or a wet paper towel, depending on how crazy you get with it.