Try this:
Put out a tablespoon of sugar with a couple of packets of nutrasweet (equal) mixed in. The ants will eat the nutrasweet-sugar mix and carry it back to the nest. The ants should be dead in a matter of a few days (maybe a week). Note that the ant flow will increase considerably for a while and then start to get thinner and thinner as they die off. Don't squish them, let them carry this poison back to the nest.
You can also mix sugar and nutrasweet (equal) in just enough water to make it dissolve and set this in a cap or lid on the counter or wherever the ants are. Roach and rat problems also solved this way, although for them you'd have to mix considerably more. It may not kill all of them, but it should definitely thin out the population.
You can also sprinkle nutrasweet liberally on fire ant mounds and they'll die as well in a few days.
Yep, folks, this is the same crap that we drink and eat in our foods. It just affects them faster than us, since they're not much more than a few proteins and chitin surrounding a central nervous system. Give it a try.