Subject: Comfrey harmful?
From: [email-masked] (Cecilia Henningsson)
Date: Sat, 10 Jul 1993 16:21:45 GMT
Newsgroups: alt.folklore.herbs

Here's an article from British gardening magazine,_The_Gardener_,
August 1993, page 85. Copyright Headway, Home and Law Publishing Ltd
1993. Reprinted without permission.

[begin quote]

Harmful hedgerow plants 
======================= 

Comfrey, commonly found in both hedgerows and gardens and often used
to make herbal teas, remedies or even eaten as a vegetable, actually
contains certain toxins called pyrolixidine alkaloids (PAs). A
committee which advises the Government on food safety issues has
concluded that there is sufficient evidence linking the intake of
comfrey with toxic efects in humans to recommend that we should not
consume preparations of comfrey which contains high levels of
PAs. Manufacturers and retailers have been asked to withdraw products
like comfrey tablest and capsules from the shops. It has also been
suggested that eating leaves of roots of comfrey could be
dangerous. Comfrey infusions were always thought to be relatively
harmless but, in view of this new information it may be wise to think
again.

[end quote]

So what are these things, pyrolixidine alkaloids? And in what
quantities does comfrey (Symphytum officinale and other S. species)
contain them? The article seems to imply that comfrey is only harmful
if taken internally, so growing them for aestethic values should be
perfectly safe. Any comfrey junkies in the group care to answer? ;)

--Ceci, thinking of planting comfrey
--
=====[email-masked]===========================================
"There is a mysterious tendency for four fingers or toes 
 to look like five." Claude Harrison in _The_Portrait_Painter's_Handbook_
===================================================================

From: [email-masked] (Bart Singer)
Date: 10 Jul 1993 18:35:23 GMT

There have been at least two studies in the U.S. that suggest a link
between comfrey consumption increased risk of cancer (specifically, I
think it was liver cancer).  The quantity of comfrey consumed was less
than 1% of total food consumed (I don't know if that was by weight or
calories).  I don't know if the test subjects (rodents of some sort)
were fed the leaves, roots, or both.  I believe that there is quiet
turning away from the internal use of comfrey, though it's external
use on sprains, strains, and broken bones is still widely suggested.
As far as I know, there is no direct health risk associated with
growing the plant and if anyone actually does grow the plant, I'd be
interested in knowing where I can get some plants (or seeds, or root
cuttings.)

From: [email-masked] (Sue D. Nymme)
Date: 11 Jul 1993 17:00:39 GMT

The following quote may be biased, so take it FWIW. It's from an essay
entitled "Comfrey as Medicine" (1979), issued by the National
Institute of Medicinal Herbalists (England).

"The strange saga of comfrey indicates the folly and illogicality of
the approach which runs as follows. If a trace of a chemical can be
isolated from a large quantity of a plant and be fed or injected into
laboratory animals, the lethal results may be extrapolated to man who
is then told not to take any of the original plant because it contains
poison. The plant may have been eaten or made into a tea for centuries
during which no single instance of ill-effect has followed its
use. Today there is no single man, woman, or child in any country who
has been recorded as suffering toxic effects from taking comfrey leaf
or root as medicind.  Comfrey has a clean sheet and has no case to
answer. The onus probandi lies upon those who denigrate a safe herbal
remedy by making assumptions in the absence of any evidence to justify
what has tended to become an emotive rather than a scientific issue."

Me, I agree. The dose makes the toxin. Anything taken in large doses
is toxic, and many toxins taken in small doses are called
medecines. (Eek!  I;m starting to sound like a homeopathist!) :-)