Can you use a puppy flea collar on cat?

No. Puppy and cat flea collars are designed for different species and may contain ingredients that are toxic to the other. Cat flea collars are designed to fit cats and are less likely to cause irritation or injury. While flea and tick collars might seem like an easy solution, they actually carry potential risks to both pets and people so talk to your veterinarian about safer and more appropriate ways to keep your pets pest free.