Nature. Research. Results. No matter how far science advances us, we always look to nature to inspire us. Purina ONE +Plus Urinary Tract Formula combines nature and research for results you can see in your cat. That includes a SmartBlend of high-quality ingredients including real chicken, 0% fillers and no artificial flavours or colours. This easily digestible formula helps maintain urinary tract health by reducing urinary pH and providing low dietary magnesium.