Well, I'm pretty sure that raw beetroot is poisonous
I sure hope not. I eat them raw all the time (it's the red ones, right?). I juice some a few times a week and you can even eat the leaves, so I just push everything down into the juicer.
Beets are also the sweetest vegetable there is (it has the most sugar). At least I heard that somewhere (Wikipedia?). It has an "earthy" taste to it that takes a little time to get used to.
I've heard that beet juice in large amounts can be poisonous though.