Semi moist functional Treats with Benefits for Adult Cats for Hairball control. Hairballs occur when hair stays in your cat’s stomach without passing through the digestive tract. The majority of the hair travels through the digestive tract with ease, but large amounts of hair can result in hairballs. This can cause vomiting as your kitty tries to remove the hair fall and result in digestive issues. Vvaan treats contain natural fibers that facilitate passage of hairball. Grain Free.