If you have a Petsmart with a clinic near you - they will sell individual doses of Frontline and Advantage. We had been long time Frontline users - and our dog got a massive flea infestation this year. We had been using it monthly. Frontline said to keep using it and "that it could take up to 6 months to get rid of them." They were pretty ugly about it too. We dosed with Advantage the next month, and the fleas were gone. So...I'm sold on Advantage now. Seems there might be some resistance going on - something is certainly strange.

CA