I have 5 cats and have found that Frontline is now non-effective, something that a lot of my friends are also finding as the fleas become resistant to it. I have been recommended to use Advocate, and have just done my first round and it is perfect. It is also a wormer, so two jobs in one! Furthermore, your vet should not charge yu for a prescription, so the cheapest online I have found so far is 365 vat at £21.39 for 6,