How Safe Is Whitening Gel?

My question is.. Is this whitening system 'ok' for use? I`ve heard great reviews on this but i just want to make sure. : D Here`s the list of the ingredients in the product.Whitening Gel: WATER (AQUA), POLOXAMER 407, GLYCERIN, HYDROGEN PEROXIDE, METHYL SALICYLATE, SODIUM SACCHARIN, PHOSPHORIC ACID. and the product is called Plus White 5 Minute Speed Whitening System.Are there any ingredients in this product that will harm teeth or gums in any way? [i.e remove enamel, etc] thanks so much : )