Is it possible to whiten your teeth naturally?

Baking Soda: Brush your teeth at least 3 times per day, floss everyday to remove stains in between teeth. Make a "paste" using baking soda and water and use it to re-brush your teeth after you brush with your regular toothpaste. Avoid using baking soda everyday. Consult your dentist.

It depends: It depends on how you define "naturally". Most bleaching modalities use hydrogen peroxide to whiten teeth from the inside out. Certainly, keeping your teeth clean helps keep them white.