What is it?
Comfrey is an herbal medicine used on the skin for bruises, wounds, muscle aches and pains, and sprains.
Other names for comfrey include: prickly comfrey, Russian comfrey, Symphytum officionale , S asperum , S x uplandicum
Ask your doctor, nurse, or pharmacist if you need more information about this medicine or if any information in this leaflet concerns you.
Tell your doctor if you
- are taking medicine or are allergic to any medicine (prescription or over-the-counter (OTC) or dietary supplement).
- are pregnant or plan to become pregnant while using this medicine.
- are breastfeeding.
- have liver disease or kidney problems.
- have any other health problems, such as high blood pressure or heart or blood vessel disease.
Talk with your caregiver about how much comfrey you should take. The amount depends on the strength of the medicine and the reason you are taking comfrey. If you are using this medicine without instructions from your caregiver, follow the directions on the medicine bottle. Do not take more medicine or take it more often than the directions tell you to.
To store this medicine:
Keep all medicine locked up and away from children. Store medicine away from heat and direct light. Do not store your medicine in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down and not work the way it should work. Throw away medicine that is out of date or that you do not need. Never share your medicine with others.
Drug and Food Interactions:
Do not take comfrey without talking to your doctor first if you are taking:
- Medicine used to lower cholesterol (examples are: simvastatin (Zocor(R)); atorvastatin (Lipitor(R)))
- Acetaminophen (Tylenol(R), also found in many cough and cold medicines)
- Amiodarone (Cordarone(R))
- Medicines used to treat some types of cancer (carmustine (BiCNU(R)); mercaptopurine (Purinethol(R)))
- Medicine used to replace male hormones (Methyltestosterone (Android(R)); testosterone (Androderm(R), Testoderm(R)))
- Methotrexate (Folex(R), Rheumatrex(R)))
- Medicine used to treat infection (itraconazole (Sporanox(R)); ketoconazole (Nizoral(R)); terbinafine (Lamisil(R)))
- Valproic acid (Depacon(R), Depakene(R), Depakote(R)))
- Before taking comfrey, tell your doctor if you are pregnant or breastfeeding.
- In July 2001, the US Food and Drug Administration (FDA) released a statement recommending that comfrey products be removed from the market because of reported liver problems (8).
- Do not take by mouth (1-4). Eating or drinking comfrey may cause liver damage (1-6).
- Do not use comfrey if you have a history of liver disease (4).
- This medicine is for use on the skin only. Do not get it in your eyes, nose, or mouth. Do not use on skin areas that have cuts or scrapes. If it does get on these areas, rinse it off right away (2,3,4).
- Do not exceed the recommended dose of comfrey (4).
Call your doctor right away if you have any of these side effects:
- Allergic reaction: Itching or hives, swelling in your face or hand, swelling or tingling in your mouth or throat, chest tightness, trouble breathing, or rash
- Dark-colored urine or pale stools (1-6,8)
- Nausea, vomiting, loss of appetite, pain in your upper stomach (1-6,8)
- Yellowing of your skin or the whites of your eyes (1-6,8)
Other Side Effects:
You may have the following side effects, but this medicine may also cause other side effects. Tell your doctor if you have side effects that you think are caused by this medicine.
- Skin redness
1. Brinker F: Herb Contraindications and Drug Interactions. Eclectic Medical Publications, Sandy, OR; 1998.
2. Blumenthal M, Busse WR, Goldberg A et al (eds): The Complete German Commission E Monographs; Therapeutic Guide to Herbal Medicines. American Botanical Council, Austin, TX; 1998.
3. McGuffin M, Hobbs C, Upton R et al (eds): American Herbal Products Association's Botanical Safety Handbook. CRC Press, Boca Raton, FL; 1997.
4. Anon: British Herbal Pharmacopoeia. British Herbal Medicine Association, Keighley, UK; 1983.
5. Weston CFM et al: Veno-occlusive disease of the liver secondary to ingestion of comfrey. Br Med J 1987; 295:183.
6. Ridker PM et al: Hepatic veno-occlusive disease associated with the consumption of pyrrolizidine-containing dietary supplements. Gastroenterology 1985;88:1050-1054.
7. Weiss RF: Herbal Medicine. Beaconsfield Publishers Ltd, Beaconsfield, UK; 1988.
8. Lewis CJ: FDA advises dietary supplement manufacturers to remove comfrey products from the market. July 6, 2001. Available at: http://www.cfsan.fda.gov/~dms/dspltr06.html (cited 8/7/2001).
9. Grube B, Grunwald J, Krug L, et al: Efficacy of a comfrey root (Symphyti offic radix) extract ointment in the treatment of patients with painful osteoarthritis of the knee: results of a double-blind, randomised, bicenter, placebo-controlled study. Phytomedicine 2007; 14:2-10.
10. Predel H-G, Giannetti B, Koll R et al: Efficacy of a comfrey root extract ointment in comparison to a diclofenac gel in the treatment of ankle distortions: results of an observer-blind, randomized, multicenter study. Phytomedicine 2005; 12:707-714.
Last Updated: 5/4/2018