My vet told me that most of the drop on flea preparations work by making the fleas infertile, which means you break the ten day cycle from egg to adult. This means that you will not always see dead fleas straight away. Some internal preparations, such as 4flea do kill the flea when it bites, and when Rufus was young and went down a lot of holes he would pick up a lot of fleas and I did not trust the drops alone and gave him a tablet which worked very well. I use Stronghold, which suits me because it does ear mites, mange and roundworm. I am not sure which Frontline it is, but round here we are told that it is not as effective as it was because there is a resistance building to it since it became so popular. It was so volatile that if I so much as opened it, my last cat would shoot off, whereas with Stronghold he never saw or smelt it coming. Other than regular sessions with the Dyson and washing bedding, I have never treated the environment since a colleague told me the sprays were very toxic. So far, I have never needed to despite having cats and a hunting dog. Fingers crossed.
