What Should I Do If I Think My Cat Has Worms?
It’s important to bring your cat to a veterinarian, who can confirm the presence of worms. Avoid self-diagnosis, since worms are not always visible or identifiable.
How Are Worms Treated?
Please don’t attempt to treat your pet yourself—your cat should be treated for the specific type of worms he has. A dewormer that eradicates tapeworms, for example, will not kill roundworms. And some over-the-counter deworming medications can be harmful. After your vet has accurately diagnosed the type of parasite your pet has, he or she will then prescribe the best course of treatment, which may include an oral deworming agent.
http://www.aspca.org/pet-care/cat-care/worms the above paragraphs are excerpts, click on link for full article
