There are two very effective methods to keep ants out of the house. They are economical and simple, and do not pollute.

1. Put vinegar around all the openings and entrances to your house. Ants produce a pheromone that smells similar to vinegar, and once the ants smell the vinegar, they will think other ants are already colonized there and won't enter the house.

2. Sprinkle red pepper flakes down around all the openings and entrances to your house, and keep them there for about two weeks. Then sweep them up. This will remain effective for a very long time. You need to do this only once or twice a year.