My dad has no problem spraying poison on bugs outside of the house, but is not allowed to be spraying poison inside the house, so when he discovered ants entering the house via the doors (of course) he told me to come up with a "no chemical" solution.
After consulting my various books and such, I found that peppermint oil is a great deterrent. The papers I consulted suggested putting a few drops on cotton balls and leaving them at the entrance point. It didn't seem like the best idea to line our doorways with cotton balls, lol, especially since we were expecting a small boy, who eats anything he finds since he can't have actual food, to visit the next day. So I made a spray instead. I did my usual 4 oz cobalt glass spray bottle, adding 40 drops of peppermint essential oil and filling with purified water. I shook it well, then sprayed it all along the bottoms of the doors. (My sister thought I may have missed a spot and also sprayed the bases of the doors when I finished.) I did see some of the teeny tiny ants when I sprayed, but by the time my sister sprayed, a minute later, they were gone.
That was three or four days ago, and no ants have been spotted.
If you are troubled with ants, you might as well give this a try!
Have a good week,