This Review Title is Avoid! Leaves black flecks on teeth and in gum line! and the content is: This stuff is HORRIBLE! I followed the directions, and didn't make a mess or have a mess in my sink, as others stated; however, I can't get it out of my gums!! The directions say to rinse several times after use, which I did. It still looks like I just ate ambunch of Oreos. I brushed my teeth with Crest FOUR times and there are still black flecks along my gum line. I rinsed my mouth with Crest Whitening mouth wash... STILL have black flakes. As if that isn't bad enough, my teeth started hurting immediately after I used is stuff. I don't know how this is even on the market. It's a complete waste of money, and now I'm afraid I'll never get the black flecks out of my gum line..There are other information for this review, one is This reviewer did purchase it and the other is 3 people think this review is helpful.