I have two cats, each time we take them to the vet, the smallest cat acts like the bigger cat is a stranger and will hiss, growl and attack him. They have lived together for 6 years, but she does this each time - anything we can do to get her to stop, or a reason why she does this? This goes on for about a week.
The scents from the animal hospital linger on your pet. You can try to bath your cat after coming home from the hospital. Vetcare