Ants in the kitchen or bathroom are attracted by either bits of food or water, so be sure to clean the countertops thoroughly after each meal and wipe the sink dry. Spraying will generally not be effective over the long term since you are not removing the nest and others ants will simply return. One of the best ways to address this problem is through the use of baits. The foraging ants ingest the bait, return to the nest, and feed it to the others including the queen. Soon the entire ant colony will be gone.

The following is an effective bait which you can make at home:

• Mix 1 tsp. powdered boric acid with 5 tbsp. honey or corn syrup.
• Heat until the boric acid is dissolved, then allow to cool.
• Add 5 tbsp. water and mix thoroughly.
• Place a few drops on small cards in the areas where the ants travel.

They should begin feeding quickly. Allow 2-3 weeks for this mixture to work, replacing the drops every 2-3 days.

Additional Resources
http://edis.ifas.ufl.edu/IG080