Comment by audunw

Fluoride occurs naturally in water, that’s literally how we discovered the effects of fluoride. People in areas where water naturally contained more fluoride had less cavities.

Anything, including water itself, is toxic (not poisonous, but I’m guessing you meant toxic, since fluoride is definitely not poisonous) in high enough doses. So you could say that about ANY mineral we may add to water to adjust its taste or health effects.

I happen to think adding fluoride isn’t worth the effort. But the hysteria against it is also really dumb.