After the couple of weeks Eve coughed up a HUGE hairball. My husband was astonished and asked me how long do you think that it took to collect?! I don't know if it was the food that helped her get that out of her system but she has been fine ever since. I am surprised at how much healthier they are looking lately. Magilla brought in a chronic virus so during spring they all get a little under the weather but they actually seem better on the food. I'm just so excited that Magilla has kept his food down. They do have a formula strickly for hard to controll hairballs but this one seems to be working quite well. Believe me when I tell you that the hairball she coughed up needed to come out whether it was the food or not, I'm grateful LOL.