Ants only come into houses for the purpose of finding food, warmth and shelter.
When they find food, they will make the most of it and will establish a trail that leads hack to their nest outside. Follow the trail to the point of entry into the house and block it off with mastic sealer. Destroy and wipe up every ant you find. They will eat this and take it back to their nests, where the poison will be spread. Traditional organic ant repellents, such as talcum powder, cream of tartar, powdered sulphur or oil of cloves, were once advised to be scattered at entry points, but there are now laws against their use.