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Generic Name: comfrey (COM free)
Brand Name:

What is comfrey?

Comfrey is a plant also known as Ass Ear, Black Root, Blackwort, Bruisewort, Consolidae Radix, Consound, Consoude, Consuelda, Gum Plant, Healing Herb, Herbe aux Charpentiers, Herbe à la Coupure, Knitback, Knitbone, Langue-de-Vache, Oreille d'Âne, Salsify, Slippery Root, Symphytum officinale, or Wallwort.

Comfrey has been used in alternative medicine as a possibly effective aid in treating back pain, osteoarthritis, or tenderness and swelling caused by a sprain injury.

Other uses not proven with research have included skin wounds, skin ulcers, cough, sore throat, gum disease, joint pain, diarrhea, and other conditions.

Comfrey may have been applied to the skin in a specific preparation to treat some of these conditions.

It is not certain whether comfrey is effective in treating any medical condition. Medicinal use of this product has not been approved by the FDA. Comfrey should not be used in place of medication prescribed for you by your doctor.

Comfrey is often sold as an herbal supplement. There are no regulated manufacturing standards in place for many herbal compounds and some marketed supplements have been found to be contaminated with toxic metals or other drugs. Herbal/health supplements should be purchased from a reliable source to minimize the risk of contamination.

Comfrey may also be used for purposes not listed in this product guide.

What is the most important information I should know about comfrey?

Follow all directions on the product label and package. Tell each of your healthcare providers about all your medical conditions, allergies, and all medicines you use.

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What should I discuss with my health care provider before using comfrey?

Ask a doctor, pharmacist, or other healthcare provider if it is safe for you to use this product if you have:

  • liver disease.

Comfrey is considered likely unsafe to use during pregnancy. The chemicals contained in comfrey may cause birth defects. Do not use this product without medical advice if you are pregnant.

Comfrey is considered likely unsafe to use if you are nursing a baby. Do not use this product without medical advice if you are breast-feeding a baby.

Do not give any herbal/health supplement to a child without medical advice.

How should I use comfrey?

When considering the use of herbal supplements, seek the advice of your doctor. You may also consider consulting a practitioner who is trained in the use of herbal/health supplements.

If you choose to use comfrey, use it as directed on the package or as directed by your doctor, pharmacist, or other healthcare provider. Do not use more of this product than is recommended on the label.

Comfrey is likley unsafe to take by mouth. Comfrey contains chemicals that can cause liver damage, lung problems, or cancer. Topical comfrey is for use only on the skin.

Do not use different forms (tablets, liquid, tincture, teas, etc) of comfrey at the same time without medical advice. Using different formulations together increases the risk of an overdose.

Call your doctor if the condition you are treating with comfrey does not improve, or if it gets worse while using this product.

Store at room temperature away from moisture and heat.

What happens if I miss a dose?

Skip the missed dose if it is almost time for your next scheduled dose. Do not use extra comfrey to make up the missed dose.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid while using comfrey?

Avoid using comfrey together with other herbal/health supplements that can also harm the liver. This includes androstenedione, bishop's weed, borage, chaparral, comfrey, DHEA, echinacea, garlic, germander, golden ragwort, hound's tongue, kava, licorice, niacin (vitamin B3), pennyroyal oil, red yeast, St. John's wort, and others.

Comfrey side effects

Get emergency medical help if you have signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Although not all side effects are known, comfrey is thought to be possibly safe when applied to unbroken skin for less than 10 days.

Stop using comfrey and call your healthcare provider at once if you have:

  • liver problems--nausea, upper stomach pain, itching, tired feeling, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes).

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What other drugs will affect comfrey?

Do not take comfrey without medical advice if you are using any of the following medications:

  • carbamazepine;

  • phenobarbital;

  • phenytoin; or

  • rifabutin, rifampin.

This list is not complete. Other drugs may interact with comfrey, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed in this product guide.

Where can I get more information?

  • Consult with a licensed healthcare professional before using any herbal/health supplement. Whether you are treated by a medical doctor or a practitioner trained in the use of natural medicines/supplements, make sure all your healthcare providers know about all of your medical conditions and treatments.
  • Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.
  • Disclaimer: Every effort has been made to ensure that the information provided by Cerner Multum, Inc. ('Multum') is accurate, up-to-date, and complete, but no guarantee is made to that effect. Drug information contained herein may be time sensitive. Multum information has been compiled for use by healthcare practitioners and consumers in the United States and therefore Multum does not warrant that uses outside of the United States are appropriate, unless specifically indicated otherwise. Multum's drug information does not endorse drugs, diagnose patients or recommend therapy. Multum's drug information is an informational resource designed to assist licensed healthcare practitioners in caring for their patients and/or to serve consumers viewing this service as a supplement to, and not a substitute for, the expertise, skill, knowledge and judgment of healthcare practitioners. The absence of a warning for a given drug or drug combination in no way should be construed to indicate that the drug or drug combination is safe, effective or appropriate for any given patient. Multum does not assume any responsibility for any aspect of healthcare administered with the aid of information Multum provides. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the drugs you are taking, check with your doctor, nurse or pharmacist.

Copyright 1996-2012 Cerner Multum, Inc. Version: 5.01. Revision Date: 2015-02-18, 1:49:00 PM.