My 10 yr old "doodle" has used this for 2 years and had NO TICKS OR FLEAS....period. Our new puppy, 4 months old is going to use this one. After clearing it with the vet. I told him of the very good results with my first dog and he said the puppy can use it as well. OK. But both MUST HAVE HEARTGUARD because it does not protect the dog from heart worm disease.