Comfrey

Symphytum officinale

Toxic

Knitbone — a legendary wound-and-bone poultice whose internal use is no longer defensible.

Handle as a poison-garden specimen. See Safety before any use.

Allantoin-rich leaf and root really do encourage cell proliferation, which is why folk healers loved it and why you must not put it on dirty or deep wounds (it can close the surface over an infection). Unsaturated pyrrolizidine alkaloids damage the liver with internal use. Grow it as a compost plant and an external poultice only.

Flavor

Cucumber-green and mucilaginous. Not a tea flavor to chase.

Parts used

Leaf (topical) · Root (topical)

In favor

Exceptional compost and mulch plant
Soothing external poultice

Against

Hepatotoxic internally
Can seal in infection
Bocking 14 is sterile — prefer it so it does not seed