DL, here is a good overview of comfrey and it's uses.

http://www.anniesremedy.com/herb_detail89.php?gc=b89

I'm using it for PAIN. Whatever is ailing me, I'm using it. It calms my pain.

I'm actually going to be working with a comfrey homeopathic soon primarily for OA pain.

It's called Symphytum Officinale. I've talked about it somewhere here.