Most folks when they hear Mullein immediately think of the leaves and flowers and its affinity to the lungs. However, the root it also incredibly medicinal and has been the part of the plant I've grown closest to on and off over the years. Mullein root is what I've found most useful for my spine, and to alleviate nerve pain that I still get here and there. When I was a teenager I had an accident and shattered my lower spine (I also split my head open and had brain bleeding). It was quite the ordeal, I was paralyzed in my legs for a short time and eventually regained feeling, learned how to walk all over again and so on. I was in the hospital for some time and they ended up doing a surgery to remove the bone shards and replacing that portion of my spine with titanium. It's been a long time, but once in a while I'll get a "flare up" and be in excruciating pain which makes it difficult to so even the most basic daily things. Mullein root is what I try to turn to when I can. 
Mullein root is excellent in facilitating proper alignment of our structural system, from spinal injury or just general life wears. It's incredibly safe, just like the leaves and flowers. 
Another highly researched use for Mullein root is as a tonifying agent for the bladder, useful for things like urinary incontinence as well as enhancing bladder function. This also is incredibly helpful for folks with chronic UTIs.
Mullein root has some amazing water soluble qualities, so I tincture it in glycerine. We have Mullein root glycerites loaded on the site :)