|| Symphytum officinale
Comfrey (Symphytum officinale) has been traditionally used to treat
wounds and to reduce the inflammation associated with sprains and broken bones.
The roots and leaves of comfrey contain allantoin, a substance that promotes
wound healing and tissue regeneration. Comfrey ointments were often applied to
the surface of the skin to heal bruises as well as pulled muscles and ligaments,
fractures, sprains, and strains. Some traditional healers also used comfrey
leaves to reduce inflammation, treat gout, and heal superficial blood clots in
the legs (called thrombophlebitis).
Despite these beneficial effects, reports began to emerge in the 1980s that
internal consumption of comfrey may be hazardous to the health. Laboratory
studies revealed that comfrey contains dangerous substances called pyrrolizidine
alkaloids that are highly toxic to the liver. Animal studies found that
consumption of comfrey may lead to a potentially life-threatening condition
called hepatic veno-occlusive disease (HVOD) in which the blood vessels around
the liver become blocked. If left untreated, HVOD can lead to complete liver
failure, even death. Outbreaks of HVOD began to appear in Europe and the United
States and researchers gradually discovered that these outbreaks were often
linked to ingestion of oral comfrey products.
Echimidine is one of the most toxic pyrrolizidine alkaloids. Dangerously high
levels of this alkaloid have been found in both prickley comfrey (Symphytum
asperum) and Russian comfrey (Symphytum uplandicum), close relatives of the
common comfrey plant. While common comfrey has been the preferred source of
comfrey herbal products, some preparations sold in the United States and Europe
may have been unknowingly contaminated with Russian and prickley comfrey. This
is because common, Russian, and prickley comfrey are very similar in appearance
and collectors who harvest raw plant material are not always able to distinguish
between the different species.
Based on reports of HVOD in the United States and abroad, the U.S. Food and
Drug Administration (FDA) recommended in July of 2001 that dietary supplement
manufacturers immediately remove all comfrey-containing products from the
market. The FDA cited evidence that the pyrrolizidine alkaloids are not only
toxic to the liver, but possibly other tissues in the body as well. They also
cited evidence that these substances may even potentially cause cancer. In
addition to the United States, countries including the United Kingdom,
Australia, Canada, and Germany have banned the sale of products containing
comfrey. Other countries permit use of this herb only under a doctor's
Comfrey is a perennial herb that originated in Europe and temperate parts of
Asia. Fond of moist soils, comfrey has an erect and stiff-haired stem, and it
grows to a height of 20 to 120 cm. Its flowers are dull purple, violet, or
whitish, and densely arranged in clusters. The wrinkly and hairy leaves are
oblong, and often differ in appearance depending upon their position on the
stem: the lower leaves are broad at the base and tapered at the ends while the
upper leaves are broad throughout and narrowed only at the ends. The slimy roots
show a horn-like appearance when dried. The root has a black exterior and fleshy
whitish interior filled with juice.
Comfrey preparations are made from the leaves or other parts of the plant
grown above the ground. Some preparations were also made from the roots, but
roots contain up to 16 times the amount of pyrrolizidine alkaloids and are
therefore more likely to cause poisoning.
|What's It Made Of?|
Comfrey contains allantoin, rosmarinic acid, and vitamin B12. It also
contains poisonous compounds called pyrrolizidine alkaloids, which are highly
concentrated in the roots of the comfrey plant. In fact, the roots contain
levels of pyrrolizidine alkaloids that are roughly 10 to 16 times higher than
the mature leaves.
Oral comfrey products have been restricted by the FDA, but topical
preparations are still available in the United States.
Comfrey ointments (containing 5% to 20% comfrey), creams, poultices, and
liniments are made from the fresh or dried herb, leaf, or root of comfrey
species. Use only products made from leaves of common comfrey.
Be sure to buy comfrey preparations from established companies with good
reputations, and who distribute their products through trustworthy and
knowledgeable establishments. Whenever possible, select products with guaranteed
potency or standardized extracts. Follow dosage recommendations on the label.
|How to Take It|
Children should never ingest comfrey or comfrey-containing products for any
There are no known scientific reports on the pediatric use of topical comfrey
ointments or creams. Therefore, it is not currently recommended for
Adults should never ingest comfrey or any comfrey-containing products.
Use only herb and leaf ointments, creams, and other topical preparations. Use
only the amount recommended on the label and never more than this amount.
Comfrey remedies should not be used for more than four to six weeks in any given
Comfrey contains toxic substances that can cause severe liver damage and
possibly even death. For this reason, comfrey and comfrey-containing products
should never be ingested. The main symptom you would feel if experiencing liver
damage from comfrey is abdominal pain just below the right side of the rib cage
because the liver enlarges from HVOD.
Because of the potential for side effects and interactions with medications,
even topical comfrey preparations should be taken only under the supervision of
a knowledgeable healthcare provider.
Comfrey is considered relatively safe if used only as a topical preparation
on unbroken skin (free of cuts or open wounds).
Pregnant and breastfeeding women should not use comfrey products under any
There are no known scientific reports of interactions between comfrey and
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|Review Date: April 2002|
|Reviewed By: Participants in the review process include: Jacqueline A. Hart, MD,
Department of Internal Medicine, Newton-Wellesley Hospital, Harvard University
and Senior Medical Editor Integrative Medicine, Boston, MA; Gary Kracoff, RPh
(Pediatric Dosing section February 2001), Johnson Drugs, Natick, MA; Steven
Ottariono, RPh, Veteran's Administrative Hospital, Londonderry, NH; R. Lynn
Shumake, PD (April 1999), Director, Alternative Medicine Apothecary, Blue
Mountain Apothecary & Healing Arts, University of Maryland Medical Center,
Glenwood, MD; David Winston, Herbalist (April 1999), Herbalist and Alchemist,
Inc., Washington, NJ; Tom Wolfe, P.AHG (April 1999), Smile Herb Shop, College
Park, MD. All interaction sections have also been reviewed by a team of experts
including Joseph Lamb, MD (July 2000), The Integrative Medicine Works,
Alexandria, VA;Enrico Liva, ND, RPh (August 2000), Vital Nutrients, Middletown,
CT; Brian T Sanderoff, PD, BS in Pharmacy (March 2000), Clinical Assistant
Professor, University of Maryland School of Pharmacy; President, Your
Prescription for Health, Owings Mills, MD; Ira Zunin, MD, MPH, MBA (July 2000),
President and Chairman, Hawaii State Consortium for Integrative Medicine,
Copyright © 2004 A.D.A.M., Inc
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before administering any drug, herb, or supplement discussed