In past years I have used Frontline but in some areas where the ticks are bad it was like putting gravy on the dog.( I did about 20 marks in a local field one night and pulled over two and a half dozen ticks off my pup, I found three dug in two days later)) My vet gave me a product called Omnitrol(Vedco,Inc), so far I have not pulled tick one off the pup. This stuff is cheaper then frontline (not paying royaltys to the French company, Sanofi)