Do mouth washes that claim to whiten really work?

If they have hydrogen peroxide as an active ingredient then they can whiten your teeth. Recently several of my patients have come in and had whiter teeth and when asked about it they explained that they had been using a whitening mouth wash. These are being sold over the counter by several manufacturers and apparently do work.

These mouth rinses may have side effects. One of my patients who had been using one came in and his outer layer of his gingiva was 'sloughing off'. He had no apparent inflammation, just a layer of tissue that could be peeled off with a dental instrument. He had no bleeding when I removed the layer and his gums looked healthy underneath. When I asked him about it , he reported that he had noticed it as well, but though it was a residue from the mouth rinse. I asked him to stop using his rinse.