While most pet owners hate to think of applying insecticides on their pets, often it’s the only way to control a flea or tick problem, particularly if your dog loves to go outside a lot. Permethrin can be one of the most effective treatments in killing and controlling tick infestations on a dog. When using an insecticide on your dogs, it’s important to be aware of safety guidelines and dosages. And if you have cats, you’ll want to note that permethrin is toxic to them, so never mix up your dog and cat flea and tick treatments. Is Permethrin Safe