I started growing comfrey because I loved the true-blue flowers---I thought the second spring that I might regret my choice, because it reseeded all over the garden. But after seeing how much the bees love it and how easy it is to pull & compost, I'm very happy I decided to scatter those first seeds.
Two years ago my neighbor cut herself, couldn't stop the bleeding, and had phoned the hospital to find they had a 2-hour wait in the ER. She knew I was into herbal healing, and phoned me. In more than one of my references, a bruised comfrey leaf was top on the list to stop bleeding. I happened to have PLENTY available at the time, and it worked like a charm.
We've used comfrey several times since then to bandage cuts, and my observations indicate it does seem to stop bleeding, promote tissue healing, and reduce scarring. As I am a world-class klutz, it's a useful plant for me to grow!