Flea collars are not the most effective way to treat a flea infestation in one's home, but they can be a key component in repelling fleas from a feline who is not currently infested. Unfortunately, many of the more powerful flea collars are made with harsh pesticides and chemicals which can irritate your cat's skin and/or cause illness without a significant increase in effectiveness. Furthermore, a cat able to reach its collar while grooming or a child snuggling too closely might accidentally ingest the toxins meant to harm only the fleas. The Natural Resources Defense Council (NRDC) recommends avoiding collars which include chlorpyrifos, dichlorvos, phosmet, naled, tetrachlorvinphos, diazinon and malathion among their list of ingredients. These organophosphate insecticides have been linked to health problems in cats, including skin irritation, difficulty breathing, cancer and poisoning. That is why I recommend only using flea collars with the goal of repelling fleas and utilizing safer oral or topical methods to treat a flea infestation. The least expensive flea collars often are made with these harsh chemicals and equally little care for safety in design. The best cat flea treatments in 2022 will be free of harsh chemicals and include a break-away mechanism so the feline can untangle itself from fence lines and tree branches if needed. The collars on this list were chosen based on their treatment method, design, price, and online reviews.