Ass Ear, Black Root, Blackwort, Bruisewort, Common Comfrey, Consolidae Radix, Consound, Consoude, Consoude Officinale, Consuelda, Grande Consoude, Gum Plant, Healing Herb, Herbe aux Charpentiers, Herbe à la Coupure, Knitback, Knitbone, Langue-de-Vache, Oreille d’Âne, Salsify, Slippery Root, Symphytum officinale, Wallwort.<br/><br/>


Overview Information

Comfrey is a plant. Even though this plant contains poisonous chemicals called pyrrolizidine alkaloids (PAs), the leaf, root, and root-like stem (rhizome) are used to make medicine. The amount of PAs found in comfrey changes according to the time of harvesting and the age of the plant. The roots have 10 times higher amounts of PAs than the leaves. Some products labeled “common comfrey” or Symphytum officinale actually contain the more poisonous “prickly comfrey” (Symphytum asperum) or “Russian comfrey” (Symphytum x uplandicum) species.

Comfrey is used as a tea for upset stomach, ulcers, heavy menstrual periods, diarrhea, bloody urine, persistent cough, painful breathing (pleuritis), bronchitis, cancer, and chest pain (angina). It is also used as a gargle for gum disease and sore throat.

Comfrey is applied to the skin for ulcers, wounds, joint inflammation, bruises, rheumatoid arthritis, swollen veins (phlebitis), gout, and fractures.

How does it work?

The chemicals in comfrey might have a healing effect and reduce inflammation when applied to the skin. However, comfrey contains toxic chemicals that can be absorbed through the skin.


Uses & Effectiveness?

Possibly Effective for

  • Back pain. Applying a comfrey extract ointment to the affected area for 5 days seems to decrease lower or upper back pain. Also applying a cream containing comfrey extract plus methyl nicotinate to the affected area for 5 days seems to decrease back pain when resting or moving.
  • Osteoarthritis. Applying a comfrey extract ointment to the affected area for 3 weeks or applying a specific cream containing comfrey extract, tannic acid, Aloe vera gel, eucalyptus oil, and frankincense oil to the affected are for 6-12 weeks seems to decrease pain in people with knee osteoarthritis.
  • Sprains. Early research shows that applying comfrey ointment to the affected area for up to 2 weeks improves mobility, decreases pain, and reduces tenderness and swelling of sprains. The effect of comfrey ointment in relieving pain and reducing swelling seems to be comparable to the effects of diclofenac gel.

Insufficient Evidence for

  • Bruises. Early research shows that applying comfrey directly to the skin for 2 weeks might decrease pain and tenderness of bruises.
  • Gangrene.
  • Broken bones.
  • Pulled muscles.
  • Rheumatoid arthritis.
  • Phlebitis.
  • Varicose veins.
  • Gout.
  • Boils.
  • Hemorrhoids.
  • Heavy menstrual periods.
  • Cough.
  • Sore throat.
  • Gum disease.
  • Joint pain.
  • Chest pain.
  • Cancer.
  • Inflammation (pain and swelling).
  • Other conditions.
More evidence is needed to rate the effectiveness of comfrey for these uses.

Side Effects

Side Effects & Safety

Comfrey is POSSIBLY SAFE for most people when applied to unbroken skin in small amounts for less than 10 days. It’s important to remember that the poisonous chemicals in comfrey can pass through the skin. Absorption of these chemicals increases if the skin is broken or if large amounts are applied.

Comfrey is LIKELY UNSAFE for anyone when taken by mouth. It contains chemicals (pyrrolizidine alkaloids, PAs) that can cause liver damage, lung damage, and cancer. The FDA has recommended removal of oral comfrey products from the market.

Special Precautions & Warnings:

Pregnancy and breast-feeding: Comfrey is LIKELY UNSAFE to take by mouth or apply to the skin if you are pregnant or breast-feeding. In addition to causing liver damage and possibly cancer, the PAs in comfrey might also cause birth defects. Even topical use is unwise, since the PAs can be absorbed through the skin.

Broken or damaged skin: Don’t apply comfrey to broken or damaged skin. Doing so might expose you to large amounts of the chemicals in comfrey that can cause liver damage and other serious health effects.

Liver disease: There is a concern that comfrey might make liver disease worse. Don’t use comfrey if you have any problems with your liver.



Major Interaction

Do not take this combination

  • Medications that can harm the liver (Hepatotoxic drugs) interacts with COMFREY

    Comfrey might harm the liver. Taking comfrey along with medication that might also harm the liver can increase the risk of liver damage. Do not take comfrey if you are taking a medication that can harm the liver.<br><nb>Some medications that can harm the liver include acetaminophen (Tylenol and others), amiodarone (Cordarone), carbamazepine (Tegretol), isoniazid (INH), methotrexate (Rheumatrex), methyldopa (Aldomet), fluconazole (Diflucan), itraconazole (Sporanox), erythromycin (Erythrocin, Ilosone, others), phenytoin (Dilantin), lovastatin (Mevacor), pravastatin (Pravachol), simvastatin (Zocor), and many others.

Moderate Interaction

Be cautious with this combination

  • Medications that increase the breakdown of other medications by the liver (Cytochrome P450 3A4 (CYP3A4) inducers) interacts with COMFREY

    Comfrey is broken down by the liver. Some chemicals that form when the liver breaks down comfrey can be harmful. Medications that cause the liver to break down comfrey might enhance the toxic effects of chemicals contained in comfrey.<br><nb>Some of these medicines include carbamazepine (Tegretol), phenobarbital, phenytoin (Dilantin), rifampin, rifabutin (Mycobutin), and others.




  • For back pain: About 4 grams of a specific ointment containing 35% comfrey root extract has been applied three times daily for 5 days. About 4 grams of another cream containing 35% comfrey plus 1.2% methyl nicotinate has also been applied three times daily for 5 days.
  • For osteoarthritis: About 2 grams of a specific ointment containing 35% comfrey root extract has been applied to the knee three times daily for 3 weeks. Also, about 3.5 grams of a specific cream containing comfrey extract, tannic acid, aloe vera gel, eucalyptus oil, and frankincense oil has been applied to the knee three times daily for 6-12 weeks.
  • For sprains: About 2 grams of a specific ointment containing 35% comfrey extract has been applied to ankle sprains four times daily for 8 days.

View References


  • Barna, M., Kucera, A., Hladicova, M., and Kucera, M. [Wound healing effects of a Symphytum herb extract cream (Symphytum x uplandicum NYMAN: ): results of a randomized, controlled double-blind study]. Wien.Med.Wochenschr. 2007;157(21-22):569-574. View abstract.
  • Barna, M., Kucera, A., Hladikova, M., and Kucera, M. Randomized double-blind study: wound-healing effects of a Symphytum herb extract cream (Symphytumxuplandicum Nyman) in children. Arzneimittelforschung. 2012;62(6):285-289. View abstract.
  • Barthomeuf, C. M., Debiton, E., Barbakadze, V. V., and Kemertelidze, E. P. Evaluation of the dietetic and therapeutic potential of a high molecular weight hydroxycinnamate-derived polymer from Symphytum asperum Lepech. Regarding its antioxidant, antilipoperoxidant, antiinflammatory, and cytotoxic properties. J Agric.Food Chem 2001;49(8):3942-3946. View abstract.
  • Behninger, C., Abel, G., Roder, E., Neuberger, V., and Goggelmann, W. [Studies on the effect of an alkaloid extract of Symphytum officinale on human lymphocyte cultures]. Planta Med. 1989;55(6):518-522. View abstract.
  • Bleakley, C. M., McDonough, S. M., and MacAuley, D. C. Some conservative strategies are effective when added to controlled mobilisation with external support after acute ankle sprain: a systematic review. Aust.J Physiother. 2008;54(1):7-20. View abstract.
  • Couet, C. E., Crews, C., and Hanley, A. B. Analysis, separation, and bioassay of pyrrolizidine alkaloids from comfrey (Symphytum officinale). Nat.Toxins. 1996;4(4):163-167. View abstract.
  • D'Anchise, R., Bulitta, M., and Giannetti, B. Comfrey extract ointment in comparison to diclofenac gel in the treatment of acute unilateral ankle sprains (distortions). Arzneimittelforschung. 2007;57(11):712-716. View abstract.
  • Giannetti, B. M., Staiger, C., Bulitta, M., and Predel, H. G. Efficacy and safety of comfrey root extract ointment in the treatment of acute upper or lower back pain: results of a double-blind, randomised, placebo controlled, multicentre trial. Br.J Sports Med. 2010;44(9):637-641. View abstract.
  • Grube, B., Grunwald, J., Krug, L., and Staiger, C. 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 trial. Phytomedicine. 2007;14(1):2-10. View abstract.
  • Gyorik, S. and Stricker, H. Severe pulmonary hypertension possibly due to pyrrolizidine alkaloids in polyphytotherapy. Swiss.Med.Wkly. 4-4-2009;139(13-14):210-211. View abstract.
  • Hirono, I., Mori, H., and Haga, M. Carcinogenic activity of Symphytum officinale. J Natl.Cancer Inst 1978;61(3):865-869. View abstract.
  • Johnson, B. M., Bolton, J. L., and van Breemen, R. B. Screening botanical extracts for quinoid metabolites. Chem Res Toxicol 2001;14(11):1546-1551. View abstract.
  • Koll, R., Buhr, M., Dieter, R., Pabst, H., Predel, H. G., Petrowicz, O., Giannetti, B., Klingenburg, S., and Staiger, C. Efficacy and tolerance of a comfrey root extract (Extr. Rad. Symphyti) in the treatment of ankle distorsions: results of a multicenter, randomized, placebo-controlled, double-blind study. Phytomedicine. 2004;11(6):470-477. View abstract.
  • Koll, R., Buhr, M., Dieter, R., Petrowicz, O., Gianetti, B., and Wagener, S. Wirksamkeit und Vertraglichkeit von Beinwellextrakt (Extr. Rad. Symphyti) bei Sprunggelenks-distorsionen. Z Phytotherapie 2000;21:127-134.
  • Kucera, M., Barna, M., Horacek, O., Kalal, J., Kucera, A., and Hladikova, M. Topical symphytum herb concentrate cream against myalgia: a randomized controlled double-blind clinical study. Adv Ther 2005;22(6):681-692. View abstract.
  • Kucera, M., Barna, M., Horacek, O., Kovarikova, J., and Kucera, A. Efficacy and safety of topically applied Symphytum herb extract cream in the treatment of ankle distortion: results of a randomized controlled clinical double blind study. Wien.Med Wochenschr. 2004;154(21-22):498-507. View abstract.
  • Kucera, M., Kalal, J., and Polesna, Z. Effects of Symphytum ointment on muscular symptoms and functional locomotor disturbances. Adv.Ther 2000;17(4):204-210. View abstract.
  • Laslett, L. L., Quinn, S. J., Darian-Smith, E., Kwok, M., Fedorova, T., Korner, H., Steels, E., March, L., and Jones, G. Treatment with 4Jointz reduces knee pain over 12 weeks of treatment in patients with clinical knee osteoarthritis: a randomised controlled trial. Osteoarthritis.Cartilage. 2012;20(11):1209-1216. View abstract.
  • Mackinnon, M. In general practice, 'always expect the unexpected'. Aust.Fam.Physician 2008;37(4):235-236. View abstract.
  • Mazzocchi, A. and Montanaro, F. Observational study of the use of Symphytum 5CH in the management of pain and swelling after dental implant surgery. Homeopathy. 2012;101(4):211-216. View abstract.
  • Mei, N., Guo, L., Fu, P. P., Heflich, R. H., and Chen, T. Mutagenicity of comfrey (Symphytum Officinale) in rat liver. Br J Cancer 3-14-2005;92(5):873-875. View abstract.
  • Olinescu, A., Manda, G., Neagu, M., Hristescu, S., and Dasanu, C. Action of some proteic and carbohydrate components of Symphytum officinale upon normal and neoplastic cells. Roum.Arch.Microbiol.Immunol. 1993;52(2):73-80. View abstract.
  • Predel, H. G., Giannetti, B., Koll, R., Bulitta, M., and Staiger, C. 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(10):707-714. View abstract.
  • Staiger, C. Comfrey: a clinical overview. Phytother.Res 2012;26(10):1441-1448. View abstract.
  • Tunon, H., Olavsdotter, C., and Bohlin, L. Evaluation of anti-inflammatory activity of some Swedish medicinal plants. Inhibition of prostaglandin biosynthesis and PAF-induced exocytosis. J Ethnopharmacol 1995;48(2):61-76. View abstract.
  • Turley, A. J. and Muir, D. F. ECG for physicians: a potentially fatal case of mistaken identity. Resuscitation 2008;76(3):323-324. View abstract.
  • Chojkier M. Hepatic sinusoidal-obstruction syndrome: toxicity of pyrrolizidine alkaloids. J Hepatol 2003;39:437-46. View abstract.
  • Food and Drug Administration. FDA Advises Dietary Supplement Manufacturers to Remove Comfrey Products From the Market. July 6, 2001. Available at:
  • Frost R, O'meara S, Macpherson H. The external use of comfrey: a practitioner survey. Complement Ther Clin Pract. 2014;20(4):347-55. View abstract.
  • Huxtable RJ, Awang DV. Pyrrolizidine poisoning. Am J Med 1990;89:547-8.
  • Jedlinszki N, Balázs B, Csányi E, Csupor D. Penetration of lycopsamine from a comfrey ointment through human epidermis. Regul Toxicol Pharmacol. 2017;83:1-4. View abstract.
  • Koll R, Klingenburg S. [Therapeutic characteristance and tolerance of topical comfrey preparations. Results of an observational study of patients]. Fortschr Med Orig 2002;120:1-9. View abstract.
  • Mei N, Guo L, Fu PP, Fuscoe JC, Luan Y, Chen T. Metabolism, genotoxicity, and carcinogenicity of comfrey. Journal Toxicol Environ Health B Crit Rev. 2010;13(7-8):509-26. View abstract.
  • Pabst H, Schaefer A, Staiger C, Junker-samek M, Predel HG. Combination of comfrey root extract plus methyl nicotinate in patients with conditions of acute upper or low back pain: a multicentre randomised controlled trial. Phytother Res. 2013;27(6):811-7. View abstract.
  • Roeder E. Medicinal plants in Europe containing pyrrolizidine alkaloids. Pharmazie 1995;50:83-98.
  • Smith DB, Jacobson BH. Effect of a blend of comfrey root extract (Symphytum officinale L.) and tannic acid creams in the treatment of osteoarthritis of the knee: randomized, placebo-controlled, double-blind, multiclinical trials. J Chiropr Med. 2011;10(3):147-56. View abstract.
  • Stewart MJ, Steenkamp V. Pyrrolizidine poisoning: a neglected area in human toxicology. Ther Drug Monit 2001;23:698-708. View abstract.
  • Stickel F, Seitz HK. The efficacy and safety of comfrey. Public Health Nutr 2000;3:501-8. View abstract.
  • Wang YP, Yan J, Fu PP, Chou MW. Human liver microsomal reduction of pyrrolizidine alkaloid N-oxides to form the corresponding carcinogenic parent alkaloid. Toxicol Lett 2005;155:411-20. View abstract.

Vitamins Survey

Have you ever purchased COMFREY?

Did you or will you purchase this product in-store or online?

Where did you or where do you plan to purchase this product?

Where did you or where do you plan to purchase this product?

What factors influenced or will influence your purchase? (check all that apply)

Vitamins Survey

Where did you or where do you plan to purchase this product?

Do you buy vitamins online or instore?

What factors are most important to you? (check all that apply)

More Resources for COMFREY

CONDITIONS OF USE AND IMPORTANT INFORMATION: This information is meant to supplement, not replace advice from your doctor or healthcare provider and is not meant to cover all possible uses, precautions, interactions or adverse effects. This information may not fit your specific health circumstances. Never delay or disregard seeking professional medical advice from your doctor or other qualified health care provider because of something you have read on WebMD. You should always speak with your doctor or health care professional before you start, stop, or change any prescribed part of your health care plan or treatment and to determine what course of therapy is right for you.

This copyrighted material is provided by Natural Medicines Comprehensive Database Consumer Version. Information from this source is evidence-based and objective, and without commercial influence. For professional medical information on natural medicines, see Natural Medicines Comprehensive Database Professional Version.
© Therapeutic Research Faculty 2018.