★★★★★
We have lots of comfrey growing and use it for a number of things.
We make poultices for sprains and bruises by putting the roots and leaves in the blender with a bit of water. We don't cook it. Then we drink the leftover liquid. Can add juice or honey, etc. , to make it taste better. We don't worry about toxicity. My daughter got a bad sprained ankle 3 days before a hike. We made the poultices twice, she drank some of the stuff. Ankle was fine for the hike.
Another daughter cured an abscessed tooth by drinking the blended comfrey roots and leaves for a few days. But be careful about planting it in an area that will be tilled. It only takes a tiny piece of root to make a new plant, and is hard to get rid of in the garden. Plant it in an out-of-the-way place where it can take over.