Why Is Toothpaste Minty?
Mint doesn't clean your teeth. It has no cleaning function at all. It's in your toothpaste because of an advertising campaign from the 1910s — and because menthol pulls a trick on a receptor in your mouth that has nothing to do with taste.
Why You Can't Grow Peppermint From Seed
Peppermint cannot produce seed. It's a sterile hybrid, and has been since the 1690s. Which raises an awkward question about the seed packets labeled "peppermint" sitting on garden center racks right now.