Diatomaceous Earth

We started having invasions of tiny ants in our house a couple of years ago. They were attracted to food, especially sweet things like honey. At first we put the little poison traps down, but even though the quantities of poison are minuscule, we didn't like having it around. Then somebody told us about diatomaceous earth (DE), also known as diatomite or kieselgur.

DE is a naturally occurring mineral consisting of the fossilized remains of unicellular organisms called diatoms. When ground into powder form, it looks and feels like talcum powder, but to ants and other pests with exoskeletons, DE is like shards of broken glass and is fatal when they come into contact with it. It's non-toxic to humans, very effective as a bug-killer, and very inexpensive.

Some people eat food-grade DE. You can read more about it in this article and this one.