Real chicken contributes protein for strong muscles, including a healthy heart. Natural fiber blend helps minimize hairballs and promotes healthy digestion. Targeted nutrition for hairball control. Purina One® SmartBlend® Hairball Formula is formulated with a natural fiber blend that helps minimize hairballs while promoting healthy digestion. Purina One® is made with real ingredients-including rice and chicken-for a healthy difference in your cat. Her good health is reflected in the way she acts, looks and feels- it's in her strong muscles, in her shiny coat and healthy skin.