Comfrey - Symphytum sp.:
Comfrey is a broadleafed large plant with hairy leaves. The hairs of the leaves
may sting and irritate if handled roughly. The stalk is hollow, and the small bell-like
flowers may be pale purple or white.
Hardy perennial, which tolerates at least some shade. Strong and deep root
system. It may be adviseable to train it into one of those wire contraptions
one commonly sees tomatos growing in, as otherwise the stalks and leaves
may tend to fall over and
smother nearby plants. It thrives in moisture, but seems to have some tolerance
for dryness if shaded. It can be an impressive plant at the back of one's
Comfrey is not used, or recommended, for any culinary use. Before its liver toxicity
was discovered, the flowers were sometimes used as a garnish in salads.
Medical Uses in Folklore:
Comfrey has been traditionally used in wound healing, both externally and
internally. While the leaves of comfrey contain the same healing effects,
it is the roots which are most potent. Typically, it would be recommended that
comfrey root be boiled, and the decoction used. An ointment may also be
made by digesting roots or leaves in hot parafin wax, then straining the
mixture and allowing it to cool. The herb is known as
knitbone for its alleged ability to help knit bones. Comfrey is said to help
Internally, comfrey allegedly helps internal wounds, and helps
to expell phlegm. It is said to be good for the blood and humors. (However,
please note the warnings below, in light of the great enthusiasm that herbal
folkloric literature, both ancient and modern, place on this herb, when considering
it for internal usage.)
Scanning the Scientific Literature:
NOTE: This is one of the 'Problem Herbs'.
There is no evidence that comfrey can actually knit bones; indeed this is
highly unlikely. Comfrey may have once seen use as an aid to reduce the
swelling around bone breaks, but it is not recommended today. All comfrey
species contain hepatotoxic pyrrolizidine alkaloids.
Even more toxic is
the compound echimidine, which is found in Russian comfrey and in prickly
comfrey, but not in common comfrey. However, proper species identification
is essential, and one cannot guarantee that it has always been done. Indeed,
one study of several commercial comfrey supplies found the presence of
echimidine in samples that were labelled (erroneously) as common comfrey.
The roots contain far more of these alkaloids than the leaves. As noted,
even the pyrrolizidine alkaloids that common comfrey contain can be hazardous
with repeated use. Liver failure is a very real risk.
Rat livers were examined after low dose administration of comfrey-derived
alkaloids (6 doses in 6 weeks). The livers exhibited vascular congestion,
mild necrosis, and loss of definition of liver cell cellular membranes.
Comfrey contains allantoin, which promotes cell proliferation. (This may possibly
be a basis for some of its wound-healing properties.)
Culpeper declares this to be an herb of Saturn.
- Tyler, V.E. The Honest Herbal.
- Wilkes, M. Comfrey -- the Cinderella of Plants. 1967. In
Herbs for Use and for Delight.
- Culpeper, N. Culpeper's Color Herbal.
- Betz JM. Eppley RM. Taylor WC. Andrzejewski D.
Determination of pyrrolizidine alkaloids in commercial comfrey products
(Symphytum sp.). Journal of Pharmaceutical Sciences. 83(5):649-53, 1994 May.
- Yeong ML. Wakefield SJ. Ford HC.
Hepatocyte membrane injury and bleb formation following low dose comfrey
toxicity in rats. International Journal of Experimental Pathology.
74(2):211-7, 1993 Apr.
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This information is not intended to replace medical advice or treatment. If
conditions worsen, or persist, consult your healthcare practitioner.
Last Updated: March 7, 1999.