Updated 18 February 2013


Comfrey is a controversial herb instigating much discussion among medics and consumers since the 1980s.


Comfrey is a controversial herb instigating much discussion among medics and consumers since the 1980s.

The controversy has been provoked by vastly opposing points of view regarding the internal administration of the herb, which nowadays is strongly discouraged, unless prescribed by a health professional.

The biological name for comfrey is Symphytum officinale, and the herb is also known as Knitbone, Knitback and Gum plant. The plant has been cultivated since around 400 BC as a medicinal herb to treat wounds and reduce inflammation brought about through sprains and broken bones. Later, the Greeks and Romans added to this by introducing the internal consumption of comfrey to abate heavy bleeding and treat bronchial conditions.

But recent research has shown that comfrey contains a toxic poison called payrrolizidine alkaloid, which may cause a condition known as hepatic veno-occlusive disease (HVOD). This is a potentially fatal condition, if left untreated.

Echimidine is one of the most toxic pyrrolizidine alkaloids and has been found in both prickly comfrey and Russian comfrey, close relatives of the common comfrey plant. It was following these findings that the FDA removed all products containing the herb from the market in the USA in 2001. This was shortly followed by the banning of related products in the United Kingdom, Australia, Canada, Germany and South Africa.

Comfrey is a perennial plant with a preference for moist soil and is native to Europe and parts of Asia. It is easy to recognise by its dull purple, violet and white flowers arranged in tight clusters along the stem. The roots and leaves of comfrey contain allantoin, a substance that promotes wound healing and tissue regeneration.

Parts used

Comfrey preparations are commonly made from the leaves or other parts of the plant above the ground. The roots are also sometimes used in preparations, but contain up to 16 times the amount of pyrrolizidine alkaloids and are far more likely to cause poisoning.

Active compounds:

  • Allantoin
  • Pyrrolizidine alkaloids; including echimidine, symphytine, lycopsamine, symlandine
  • Phenolic acids; rosmarinic, chlorogenic, caffeic and lithospermic acids
  • Choline
  • Asparagine
  • Volatile oil
  • Tannins
  • Steroidal saponins
  • Triterpenes
  • Vitamin B12


  • Vulnerary
  • Demulcent
  • Anti-inflammatory
  • Astringent
  • Expectorant

What is comfrey used for?


  • Wound-healer
  • Sprains
  • Swelling
  • Bruises


  • Gastric complaints
  • Hernia
  • Ulcers
  • Bronchitis and irritable cough
  • Intestinal troubles


Apply this product to the skin, as directed.


Don't apply comfrey to large areas of your skin without first consulting your doctor or pharmacist. Comfrey is not recommended for use during pregnancy.

Comfrey contains a harmful toxin called payrrolizidine alkaloid that may cause liver disease and even death. Comfrey products should not be taken internally before consulting with a medical specialist.

Because of the potential for side effects and interactions with medications, even topical comfrey preparations should be applied only under the supervision of a knowledgeable healthcare provider.

Herb-drug interactions:

Before using this product, discuss all of the prescription and non-prescription medications you may use with a healthcare practitioner.

- (updated by Birgit Ottermann, Health24, August 2010)


Read Health24’s Comments Policy

Comment on this story
Comments have been closed for this article.

Live healthier

Exercise benefits for seniors »

Working out in the concrete jungle Even a little exercise may help prevent dementia Here’s an unexpected way to boost your memory: running

Seniors who exercise recover more quickly from injury or illness

When sedentary older adults got into an exercise routine, it curbed their risk of suffering a disabling injury or illness and helped them recover if anything did happen to them.