Overview:

Comfrey (Symphytum officinale ) is used to treat wounds and reduce the inflammation associated with sprains and broken bones. The roots and leaves contain allantoin, a substance that helps new skin cells grow, along with other substances that reduce inflammation and keep skin healthy. Comfrey ointments were often applied to the surface of the skin to heal bruises as well as pulled muscles and ligaments, fractures, sprains, strains, and osteoarthritis.

Historically, comfrey was also used to treat gastrointestinal illness. However, the herb contains dangerous substances called pyrrolizidine alkaloids that are highly toxic to the liver and can cause death. In July 2001, the U.S. Food and Drug Administration required that dietary supplement manufacturers immediately remove all oral comfrey products from the market. The United Kingdom, Australia, Canada, and Germany also have banned the sale of oral products containing comfrey.

Pyrrolizidine alkaloids are also absorbed through the skin, and harmful amounts may build up in the body. You should take care when using an ointment containing comfrey (see "How to Take It" section), and you should never use it on broken skin.

Plant Description:

Comfrey is a perennial shrub that is native to Europe and temperate parts of Asia. Fond of moist soils, comfrey has a thick, hairy stem, and grows 2 - 5 feet tall. Its flowers are dull purple, blue or whitish, and densely arranged in clusters. The leaves are oblong, and often differ in appearance depending upon their position on the stem: Lower leaves are broad at the base and tapered at the ends while upper leaves are broad throughout and narrow only at the ends. 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. New leaves tend to have more of the poisonous pyrrolizidine alkaloids than older leaves. Some preparations were also made from the roots, but roots contain up to 16 times the amount of pyrrolizidine alkaloids.

What's It Made Of?:

Comfrey contains substances that help skin regenerate, including allantoin, rosmarinic acid, and tannins. It also contains poisonous compounds called pyrrolizidine alkaloids.

Available Forms:

Oral comfrey products have been banned in the U.S. and many European countries, but topical preparations are still available.

Comfrey ointments (containing 5 - 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. Follow dosage recommendations below.

How to Take It:

Pediatric

Never give a child comfrey by mouth, and do not apply creams or ointments containing comfrey to a child's skin.

Adult

Never take comfrey by mouth. Severe liver poisoning and even death may occur.

Use herb and leaf ointments, creams, and other topical preparations. Toxic alkaloids can be absorbed through the skin so it's important to follow these safety recommendations:

• Never apply comfrey to broken skin.
• Use only small amounts of comfrey-containing creams for no longer than 10 days at a time.
• Do not use any comfrey product for more than 4 - 6 total weeks in a year.

Precautions:

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 taken orally.

Comfrey contains toxic substances that can be absorbed by the skin, so even topical preparations should be used for only a short time under the supervision of a knowledgeable health care provider.

Comfrey should never be applied to open wounds or broken skin.

Do not use comfrey if you have liver disease, alcoholism, or cancer.

Children, the elderly, and pregnant or breastfeeding women should not use comfrey products -- either orally or topically -- under any circumstances.

Possible Interactions:

There are no known scientific reports of interactions between comfrey and conventional medications. Some herbs that have also been known to cause liver problems, such as kava, scullcap, and valerian, should not be used while using comfrey ointment or cream because of the increased potential for liver damage.

Alternative Names:

Knitbone; Symphytum officinale