According to Bayer Animal Health, Advantage and Advantix are now available over-the-counter. Formerly available only through veterinarians, these flea and tick products will now be sold at pet specialty retail and internet outlets. But remember: Your veterinarian is still your best source of information about your pets health and wellness, including flea and tick prevention. Please consult with your veterinarian to make sure youre using the right product at the correct dose for your pet. Remember that improper product use can cause illness or even death. Its important to follow product directions very carefully and consult with your veterinarian immediately if you notice any signs of illness in your cat.