I still think that Frontline is working adequately for fleas. It seems that as more and more people have been spraying their lawns with the active ingredient in Frontline, fleas and ticks have begun to develop resistance to the insecticide. Ticks seemed to have developed the resistance faster. There are new products out there that may be more effective such as Vectra, and many others that can be tried.
Since you have just purchased Frontline, try applying the Frontline every 3 and 1/2 weeks instead of waiting for 4 weeks.
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