OMG peppermint or tea trea on their cat!...absolutely no essential oils should ever be used on a cat without special instructions from your vet or aromatherapist who knows exactly what it is intended for. There are very few, if any, essential oils truly safe for cats. Essential oils should be used carefully with humans also. They are extremely strong, work like medicine, and can be dangerous if used incorrectly or internally, to people and especially pets. However, there is a Rescue Remedy especially for pets, says it right on the box, which is also alcohol free, unlike the human version. My vet gave approval when he knew I was giving it to my girl to help keep her calmer when she was getting close to the end. I think it helped her a lot.