If your cat throws up a hairball every now and then, you have no need to worry but cats eat somethings that can make them sick.  If your cat throws up hairballs a couple of times a week, this is still considered normal cat behavior but if he is consistantly throwing up, it may mean that he ate something that he shouldn’t have. Dr. Elaine Mitchell , a Feline Practice Specialist in Orange, California says that they remove bottons, coins, rubber bands and all kinds of  items from cats intestinal tracks.  My cats love to chew on rubber bands, I have to make sure that I don’t leave rubber bands around the house. This can be very dangerous if a cat swallows it. If your cat is throwing up consistantly, don’t reach for the hairball pet medication yet. Take him to a vet for an xray. He may have swallowed something that he shouldn’t have.