I had the same problem with frontline! I now use Advantage (spelling) and I have not had the problem. My neighbor has lots of cats and tall grass so i went to Home Depot and they helped my husband pick out a spray that could be sprayed around the parameter of our yard. My vet also gave us an add'l tick collar for add'l safety during the height of the season. Good luck, call your vet and visit your local pet store.
