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Comfrey

What is comfrey?

Comfrey is a perennial herb native to Europe and Asia. It grows up to four feet tall in some regions and contains purple-white flowers arranged in dense clusters. Its root is slimy and has a horn-like appearance, with a black exterior and a fleshy white interior.

Why do we need comfrey? What is it used for?

Comfrey has traditionally been used to treat superficial wounds, as well as the inflammation that accompanies sprains and broken bones. Recent studies conducted in animals show that comfrey has healing and pain-relieving properties and stimulates the actions of certain liver enzymes. Other studies suggest that comfrey may be useful in treating gastrointestinal disorders and peptic ulcers.

How much comfrey should I take?

Daily dosage of comfrey products should not exceed 100 micrograms of pyrrolizidine alkaloids (PAs) for more than four to six weeks per year. Pyrrolizidine alkaloids are poisonous compounds that can cause severe liver damage.

What forms of comfrey are available?

Comfrey is available via ointments (containing between 5-20% comfrey), creams, poultices and liniments. You should use only products that are made from the leaves of common comfrey.

What can happen if I take too much comfrey? Are there any interactions I should be aware of? What precautions should I take?

While some people think comfrey is a beneficial herb, studies have shown that it can be quite toxic. Other comfrey species have dangerously high levels of a compound called echimidine. Some comfrey preparations, especially those taken internally, can lead to atropine poisoning (or even death).

When taking comfrey, always make sure to use reputable commercial brands that employ good quality manufacturing practices. Use only the amount recommended on the label. Never use any comfrey preparation on broken skin. If you are pregnant or nursing, do not use any comfrey products. Do not use products made from comfrey root, and do not use comfrey remedies for more than four to six weeks in any given year.

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References

• Furmanowa M, et al. Mutagenic effects of aqueous extracts of symphytum officinale L. and of its alkaloidal fractions. J Appl Toxico1983;Jun;3(3):127-30.
• Goldman RS, et al. Wound healing and analgesic effect of crude extracts of symphytum officinale. Fitoterapi 1985;(6):323—329.
• Olinescu A, et al. Action of some proteic and carbohydrate components of symphytum officinale upon normal and neoplastic cells. Roum Arch Microbiol Immunol 1993;52:73—80.
• Ridker PM, et al. Hepatic venocclusive disease associated with the consumption of pyrrolizidine-containing dietary supplements. Gastroenterology 1985;(88):1050—1054.
• Schulz V, Hänsel R, Tyler VE. Rational Phytotherapy: A Physician's Guide to Herbal Medicine, 3rd ed. Berlin: Springer; 1998:262.