You can use scouring rush for toothpaste.

I'm trying out a new toothbrush/toothpaste combo. It's nice and stiff, just how I like it. Taste is surprisingly neutral. Good and cheap, as it's all over my yard. And it leaves your spit a fun green color.

I just started rubbing it on my teeth, but if you want to try it out yourself, here's the recipe that was in my new handy dandy edible plants of the Rockies book (it's got to be better than that awful salt and baking soda combination):

Ask for clay meant for toothpaste at your local herbal store,

(I found 10 oz. for $10).

Dry and crush scouring rush to a powder.

Mix equal parts scouring rush and toothpaste clay.

Add a few drops of any essential oil that you want it to taste like

(mint, for example),

And just enough water for a thick paste.

Store in the refrigerator.

Also good (when dried) for scouring and scrubbing aluminum and copper, or for polishing wood.

(Thanks, Mark, for the new book. Who knew scouring rush was so useful? Actually who knew horsetails were actually scouring rush, which is very useful.)