We
had ants until last week.
My husband did some research, and this is what he came up with Borax with sugar water.
OR while at Down to Earth he found this stuff... terro ant killer. Borax and sugar water in a 1 oz bottle, cost him 3.49
http://www.terro.com/products.php?product=liquid_ant_killer
The ants swarm, let them eat, they worker ants take it back to the nest, feed the queen and presto! no more ants. The swarm was less than 2 inches wide, and we placed it in a corner, behind the kitchen aide.
yes, it is a chemical, but a naturally occurring one, and the safest pesticide out there. After being religious (hard for an atheist like myself) about keeping the kitchen clean, and bleaching all the counter tops daily, I thought this might be less toxic to the family.