I've tried a few whitening mouthwashes, all of them alcohol-free, and this Rembrandt is my favorite.  I've been using it for a month, twice a day, and it makes my teeth glow (added bonus is the fluoride! so don't eat or drink for 30 minutes after using this).  I drink 4 cups of tea a day but I have orthodontic braces and therefore can't use whitening strips, so the whitening mouthwash is the way to go for me.  I don't think this stuff burns - only if I've recently burned my tongue on hot food, *then* this mouthwash kinda irritates the burned tongue.  And it's the most pleasant tasting whitening mouthwash I've used (Optic White was the worst!).  It foams up a LOT but that's the nature of the whitening mouthwash, they all do that.