Herb
Knitbone — a great sprawling healer with a hard rule attached.
These are associations the community holds, not settled fact — the more a reading is shared, the bolder it sits.
Comfrey is a big, coarse, bristly plant with drooping bells of cream or purple and a root like a black parsnip. Its English names — knitbone, boneset, bruisewort — all say the same thing, and the reputation goes back at least to the Greeks: the root, mashed into a paste, was bound over sprains and fractures and sets hard as it dries, which is at minimum a splint.
Gardeners value it for a different reason. Comfrey roots go down several feet and pull up potassium, and the leaves rot into an evil-smelling liquid feed that is the mainstay of a lot of organic tomato growing. It is a plant that improves the ground it is on.
The hard rule is this: comfrey contains pyrrolizidine alkaloids, which damage the liver cumulatively, and it is no longer considered safe to take internally at all. That is a genuine change in knowledge rather than a fashion, and it does not affect the plant's long external history. Older books recommend comfrey tea. Do not follow them.
Readings practitioners have offered, ordered by how many recognise them. Take what serves, leave the rest.
Carried forward
Duskveil safety note
Almost every herbal written before the 1980s recommends comfrey tea, and a great many websites still copy them. The liver toxicity of pyrrolizidine alkaloids is now well established. This is the clearest case in the Compendium of tradition being straightforwardly wrong.
Carried forward
Nicholas Culpeper, The Complete Herbal (1653)
Culpeper calls comfrey an herb of Saturn under Capricorn, cold, dry and earthy, and reports the standing claim that the root is so binding that pieces of meat boiled with it will join together again. He does not say he has tried it.
Credit what you carry. Much of this comes from living traditions, and some of it from traditions that are closed — held by particular peoples and not offered for general use. Where you know whose practice a reading came from, name them; where you don't, say that too.