LOS ANGELES » Hairballs are normal in cats, but they’re a nuisance for cat owners to deal with. There are a few things you can do, though, to reduce hairballs and other feline dietary upsets.

Cats ingest a lot of hair because their tongues have tiny tentacles (papillae) that act like brushes when they clean, explained Dr. Karen Halligan, author, TV consultant and director of veterinary services for the Society for the Prevention of Cruelty to Animals, Los Angeles.

When hair builds up in a cat’s stomach, it turns into balls or wads, causing the cat to vomit. Once a week is normal and nothing to worry about, "but more than once a week is too much," Halligan said.

A number of over-the-counter dietary supplements such as Petromalt can be given to cats to help prevent hairballs, but Halligan uses a simple home remedy. She puts a dab of petroleum jelly on her fingertip and lets her cats, Kinky and Nathan, lick it off.

Lynea Lattanzio has a lot of experience with hairballs as founder of a sanctuary where 1,000 cats live called Cat House on the Kings, located on the Kings River in Parlier, Calif. "I give people a lot of advice on hairballs," she said. "You can put mineral oil on their food to help them slide it out, or Vaseline on their shoulder so they can lick it."

Just "don’t put it on their paws," she added. "They shake and it gets all over the walls. Put it where they can’t shake it off."

Halligan and Lattanzio agree brushing is probably the best remedy.

"I brush mine every day. It pulls out all the dead hair so they don’t ingest it when they groom," Halligan said.

If your cat doesn’t like being brushed, you might be pressing too hard or using the wrong type of brush, she said.

At Cat House on the Kings, the 20-plus employees — including one who does nothing but change litter boxes all day long — don’t have time to brush all the cats, and the feral cats wouldn’t allow it anyway. But this is the time of year when cats are shedding their coats, so workers brush as many cats as they can each week, Lattanzio said.

"Their hair goes poof, it seems to come off of them in clouds. If you don’t remove it by brushing, then they will remove it by grooming, and then they will eat it and they will get hairballs," Lattanzio said.

If a cat is vomiting and there is no hair in it, hairballs probably aren’t the problem.

"The most common is kidney disease, then pancreatitis and then food allergies," Halligan said. Even flea sensitivity can cause a cat to vomit — and go bald.

SOME owners swear by grain-free food as a way to reduce tummy troubles, or by adding bran or fiber, pumpkin, prunes, psyllium hulls or slippery elm to the cat’s diet. But Halligan advises consulting with a vet before making dietary changes.

She’s added pumpkin to cat food to remedy constipation, but she noted that cats are carnivores, programmed to eat animal protein, and might have trouble processing carbohydrates.

Halligan’s cats eat only canned food. She recommends pet owners feed their pets at least 50 percent canned food — and believes 75 percent would be better.

Hairballs can also get stuck in a cat’s intestines. A cat that stops eating for 24 or 48 hours and repeatedly vomits is at risk for dehydration and liver failure. In as little as three days, jaundice can set in, with telltale symptoms of yellowing of the gums, ears and whites of the eyes. Fast treatment by a vet is essential.

"If you get them to us on time, we can probably save them," she said.