Sentry Petromalt Fish Flavored Hairball Relief for Cats is an original formula that cats adore. When cats groom themselves, they can swallow their hair and it will enter their passageways. This hairball relief uses Petromalt technology and is an intestinal lubricant that will help hairballs from forming and eases the passage of hair that is ingested. This also helps relieve the dry cough, constipation, and vomiting that is associated with hairballs. It is effective and safe for kittens and cats 4 weeks and older. Great fish flavor that they love!