Cat repellent collars may poison cats, because repellent collars contain ingredients such as pyrethrin and amitrazine. If the cat accidentally licks the collar, it may be poisoned, and some cats are allergic to it. There are allergies to repellent collars, so it is best not to use repellent collars on cats.
Tip:
If you want to deworm your cat, it’s better to use cat-specific external deworming drops and put them in a place where the cat can’t lick them, which is safer.