Carpet pet stains are likely if you have an indoor pet. No matter how well trained an animal is, sooner or later they will have an accident. Fast response on your part will keep the stain from remaining in your expensive carpeting. Hydrogen peroxide will remove many pet stains. Pour some on a dry cloth and dampen the stain with it. Allow it to sit a bit and then blot the stain. You may have to repeat this process several times, if the stain is heavy or old. You may also have to actually pour a bit of hydrogen peroxide directly on the stain, and then soak it all up with a heavy, dry cloth.