My wife is deathly afraid of what she calls creepy crawlies. Ants, spiders, cockroaches, silverfish, pincher bugs, fleas, etc. She lived in a converted barn for a time and often awoke to ants crawling on her. So imagine the terror she felt, when after moving into our new 30 year old home, the first really good rain came and we discovered ants in the cupboards in the kitchen and bathrooms. It was them or me she said. My orders were clear; kill them all, get them out, and keep them out or sleep on the couch.
1. Kill them kill them all. If you see just a few ants it is possible that they are just scouting for a food source and if they have found it and are headed out of the house then kill them before they can tell the nest. Insect spray is fine for killing the bugs just beware of where you spray the stuff you do not want to poison children, pets, or yourself. Once you have killed them all, whip down the area with your favorite house hold cleaner. I have also left a couple of dead ones where other ants can find them in hopes that the bodies of their comrades would scare them off. I cannot really say that it helped much though.