What is the best treatment for fleas? My 14 year old vockerpoo caught fleas. I never missed his monthly Frontline treatment. The vet said it was because I bought it from COSTCO . COSTCO said it was because he was immune to it???? What should I do?

Blue dawn dish soap will at least get the fleas off him. Make sure it's the Dawn brand. Then call your vet and buy from them. The products the vet has usually come with guarantees from the manufacturer. Good luck, fleas can take up to 6 months to get out of your house.

Trust a veterinarian. Pretty sure their license means more to them than Costco's