IS YOUR CAT PRONE TO HAIRBALLS? Cats spend a large portion of their day grooming, and therefore can swallow a large quantity of hair. This ingested hair can accumulate in the digestive tract, forming hairballs which can be either regurgitated or eliminated through the stools. For some cats, the accumulated hair leads to discomfort and more serious problems. ．PROVEN RESULTS : The exclusive use of ROYAL CANIN® HAIRBALL CARE wet formula reduces hairball formation in 14 days.