ROYAL CANIN Hairball Care in Jelly is a nutritionally complete and balanced formula specially designed to help reduce hairball formation. This diet is formulated to help stimulate intestinal transit to help naturally eliminate ingested hair.ROYAL CANIN Hairball Care has proven results. Our study* showed that this diet reduced hairball formation in participating cats in just 14 days of being fed with the Hairball Care wet formula.ROYAL CANIN Hairball Care is also available in gravy, or as a dry kibble diet. A mixture of both wet food and dry food provides the variety cats love.