I adopted a mature stray this year. He was a great cat, but scruffy, and his bowel movements were absolutely toxic. I was feeding him Purina One, but on the vet's recommendation we switched to Royal Canin, and the difference in the cat is amazing. His coat is thick and soft, he no longer sheds, his dandruff is gone, and we don't need gas masks to clean his litter box. I would never have believed that a change in food could make so much difference, but it did. Great stuff.