My cat has worms. Now what?

Today I noticed a worm coming out of my cats butt. He is 4 years old. Neutered(not sure if that matters) House cat. He goes once every 6 months for visits. I am wondering what causes this? What can prevent it(he's been on preventative medicines for it) and How do we treat it?

He could've gotten worms from eating something like a bird, mouse, etc. I'd take a stool sample in to your vet to determine what kind of worm. Do not use OTC wormers - they often do far more harm than good.

Also - fleas can cause things like tapeworms.

My cat gets his drontal tablet from the vet and takes it every three months. Mine is an indoor and out door cat though so it is really for when he catches the mice and things. I totally agree with above post about worming tablets from over the counter, I don't trust them at all. Mine are direct from the vet and not expensive. Once kitty has the tablet the worms should be cleared up within a few days, mine had it once and that is how long it took. The vet also says to treat again in three months as the tablet may well have got all the worms but a second treatment would be needed for the lavae, eggs that are still growing!

IMO its better to take your cat to the vet's if you see or suspect worms. There is more then one kind. The vet will give you that appropriate dosage. Don't use the OTC wormers as you don't know what kind the cat may have.

Worms come from fleas (injecting them) (tapeworms) or from eating mice, birds or other prey (roundworms). Heartworms come from mosequitos.

Is your cat and indoor/outdoor cat? Does he have fleas (or ever had fleas in the past).

I would not do a routine worming unless the cat has worms. You are actually giving the cat a certain dosage of poison to kill the worms and cats could build up an immunity to the medicine.

I would take him to the vet.
You need to know what kind of worms they are.

Hey is 100% indoor. Does not ever go outside outside of a kitty box. We have had him since he was 6 weeks old, and he goes to the groomer every 2 months. He has never been known to have fleas. He has been on a wormer from our vet since he was 9 months(he had a real bad digestive problem) I called our only local vet and left a message this morning, but have received no call back. I can call an out of town vet and get him in asap if it's that big of a deal., he will hate being in the box for a 1 1/2 hour drive though.. Can he get sicker by waiting a couple of days?

THANK YOU ALL FOR YOUR REPLIES!