Does your cat have “bad hairball days?’ This is very common because cats are very fussy and groom themselves constantly with their tongues so they can inadvertantly swallow a lot of hair. This can cause terrible hairball problems. If you hear you cat gagging, it’s probably a hairball. This is not only a problem for long haired cats because a cats hair is replaced roughly every thirty days or so.  Even if your cat has short hair, it could ingest a lot of hair and cause the same problems. Usually the hair will pass through the gastrointestinal track without incident but sometimes it gathers in balls that your cat has to cough up. If the cat does not cough up the hairballs, they will block up the intestinal track and cause constipation. The best way to avoid hairballs is to brush your cat frequently. If this doesn’t stop the problem, I would suggest that you ask your vet for a special pet medication such as a laxitive or product that will make the hair pass through the intestinal track without causing any problems.