Most of the time, fluoride is a good thing. It makes your teeth stronger so that they can better resist the development of cavities. Common sources of fluoride are drinking water, where it is sometimes added, and an ADA-approved toothpaste. But too much of a good thing is sometimes bad, and that’s the case with fluoride. How do you get too much? Generally speaking, you’re fine unless you’ve swallowed some toothpaste or a mouthwash that contains it.

If you’ve ingested too much fluoride, in fact, you may develop a condition called fluorosis. Although it won’t hurt your health, it will affect your appearance by staining your teeth or making them darker than they should be. The first thing to do when that happens is to reduce the amount of fluoride going into your body. The second step is to talk to your dentist, who can help make your smile bright again.