mel150 I have used "andro" ant killer with success every single time, usually I sprinkle the ant hole with about 3 pinches of it ant, I mean and, within a day they are gone completely however due to is toxiticy it is not recommended around kids or pets, which I have both, but since I put it at the source ant hole outside and then cover it I have had no problems!!!! I have used it once this year and last time I used it was 3 years ago, so I guess it has to be re-used every couple of years, and I had a very persisten problem at first with the ants coming everywhere in the house then andro came to the rescue!!!