Cats can develop hairballs from routine grooming. After swallowing loosened fur and ingesting it, the fur becomes caught in the cat's stomach and forms into a ball.
Hairballs are usually passed naturally but, occasionally, a cat may have difficulty passing one through the digestive tract; it may then be coughed up, much to the dismay of owners who are left to clean up the mess.
Can Hairballs be Prevented?
One way to help prevent hair from collecting in your cat’s belly is to groom your cat on a regular basis. The less amount of hair that can get in your cat’s mouth the less chance that hair can form a hairball in the stomach.
Hairballs May Indicate a Health Issue
Many cat owners assume that regular hairball hacking is normal. Be careful, cautions Dr. Jennifer Hawkins, an Orange County, Calif., veterinarian who works closely with cats and has three cat companions at home.
"Vomiting is not normal behavior for cats," says Hawkins. "If your cat vomits more often than every eight weeks, she might have a chronic underlying problem."
If cat owners notice that food is also being coughed up along with a hairball, then it's not really a hairball.
Chronic intermittent vomiting, explains Hawkins, may be caused by organ dysfunction, inflammation of the pancreas, inflammatory bowel disease, gall bladder disorders and cancer.
Remember: Cats are very good at hiding health problems. They may appear fine even after vomiting. Contact your veterinarian if you notice that your cat is vomiting and schedule a routine checkup.
(Portions of the above post were from an article entitled, Cats and Hairballs, from PetInsurance.com.)