Cats spend much of their time grooming themselves which can result in large amounts of hair being ingested. The cat’s hair does not easily pass through the gastrointestinal tract and it is not digested.
Most of the hair that is swallowed is expelled in the stool. Sometimes it will form a dense hairball or mat in the stomach. The hairball is vomited after a fit of coughing and choking.
Not only is the vomiting of a hairball unpleasant, hairballs can also block the intestinal tract and cause serious problems.
Effective ways to keep hairballs from forming;
Brushing to remove loose hair is the fastest and easiest way to reduce hair ingestion. It also keeps the extra hair off your furniture. There are many specialized grooming tools available to help remove the extra hair.
Petroleum based laxatives (such as Laxatone) coat the ingested hair and stool allowing it to pass through the digestive system. Also used as a stool softener.
Make sure your cat drinks plenty of fresh clean water. You may want to consider a drinking fountain for running water to increase water intake.