I was VERY skeptical that this would work, as we had some pretty bad stains on our carpet. Sprayed in on, small urine spots were gone overnight. More damaged areas took several applications and have almost completely disappeared. I never would have believed it and really wish I had taken before and after photos. A slight smell after the first application, but it wasn't a bad smell, kind of a wet blanket smell...then absolutely nothing. Can't smell any ammonia when we walk in anymore. Nothing else has worked, or the product actually damaged the carpet. We also found a small little urine spot on a white linen throw pillow (the little chihuahua girl sits on top of the pillows all over) and it completely came out within a few hours and one application of about 5 sprays.