I use cheap Cinnamon from Wal Mart , works wonders and I also put it in/around new plants when planting. Works wonders.

we take grits with us camping and treat the ground.... no ants!!! it would probably work inside as well and it is a lot cheaper than pesticides

ants
 

now my spelling leaves a lot to be desired but this works! Ditomachaches earth. It used be be used in swimming pool filters but now you can buy it at lawn and garden centers. All natural. It really works

We have success with a small amount of borax mixed with 1/4 cup of honey. Just drop a small amount at various points on their path. Our problem was especially bad, so it took two treatments.

As Jingle said, please do be careful not to place this anywhere if pets may come into contact with it.

Well, we have a cat and most of the areas with ants are carpeted -- so that limits us somewhat. I am going to check out all the suggestions, though. Thanks!

I know of someone that uses baby powder.

Another vote here for borax, I've mixed it with sugar and sprinkled it around entry points into the house and into ant trails. They take it back to the nest and it kills them. But do keep out of reach of pets!

Ants tend to be attracted to water. Is there somewhere that water is leaking in causing them to make colonies. I only know this because I had a coffee maker that leaked and the water ran under the counter-top microwave. When I moved the microwave there were hundreds of ants. Once we killed them off and dried up the counter they were totally gone. Look for wet areas and good luck.

I found that it was great to wash my floors with hot water and vinegar and then my counters with vinegar. I then sprinkle the counter (where they walk across on their way to the sink), with baking soda. Apparently it is like walking on glass for them. I did add the dome baits and sprayed the outside of the house. I try not to leave anything in the sink and with all of this, was able to rid them. Preventative spraying in the spring helps before they come in. I find them more prevalent in rainier springs.

Ortho makes a peanut butter poison in a round container. The only place I can find it is at Home Depot. It is safe to use around pets. It claims to kill the queen. It is the only thing that has worked for me.