This works much better than the Colgate fluoride gel to reduce sensitivity. For some reason someone had the bright idea to add color to this gel. The mint is green, so all around my teeth are green after using. It doesn't stain, but you can't rinse, or brush, for at least 30 minutes, as with most fluoride treatments. So you have to have green, or which ever color coressponds to the flavor you choose, for at least 30 minutes. It is somewhat difficult to brush it all off. It says the coloring is added to make sure patients don't have allergies. I brought the bottle to my dentist (who I have been going to for over a decade), and she was SHOCKED by the coloring, and had all her staff come in to see it. They had never seen anything like it, and could think of no good reason for the coloring. She gave me a free sample of clear fluoride gel to use. She was concerned because the color was somewhat difficult to brush off, and I actually injured my gums from brushing so vigorously to remove the color before leaving my house. I have been using fluoride gel for more than 20 years for sensitivity, and have never had any that was colored like this before. It does significantly reduce sensitivity, if you can stand the temporary discoloration.