How do you prevent hairballs in cats?
Quick answer
Hairballs form when a cat swallows loose fur while grooming and the fur clumps in the stomach instead of passing through the gut, so brushing your cat several times a week is the single most effective way to prevent them, backed up by hydration, fibre and more play.
The full answer
Brushing is the front line. Every session removes fur your cat would otherwise swallow, so aim for two or three times a week, or daily during shedding season and for long-haired breeds. A deshedding tool once or twice a week reaches the loose undercoat a normal brush misses, and keeping up with flea treatment matters too, because itchy skin makes cats groom far more than usual.
Water and fibre do the rest. Cats that drink well move swallowed hair through the digestive tract more easily, so offer a circulating water fountain, add water to wet food, and feed wet food alongside dry. Fibre helps hair travel through the gut: a teaspoon of plain canned pumpkin, a vet-recommended psyllium supplement, or a commercial hairball-control diet are all reasonable options. A hairball lubricant or laxative paste from your vet can help a cat that already has a problem. Some cats nibble grass, which can help them bring a hairball up, so keep a safe, untreated pot of cat grass available.
Know when to worry. An occasional hairball, roughly once every week or two in a long-haired cat, is normal, but frequent retching, retching that produces nothing, coughing, lethargy, loss of appetite or constipation can mean asthma or a blockage, which is an emergency. Never give petroleum jelly, mineral oil or human laxatives without veterinary guidance, because they can be dangerous if inhaled or given at the wrong dose.