Latin Name: Symphytum officinale
Family: Boraginaceae
Comfrey has long been used as a folk remedy for pain, inflammation, and to treat wounds. In human studies, it has shown to reduce swelling after ankle injury, reduce knee and back pain, and shorten the time of wound healing.
RESEARCH
The listings of research below represent a compilation of scientific articles found on the species, with a very brief overview description of each article/study. Research found is catalogued by therapeutic action. This categorized compilation of research articles does not necessarily imply that there are adequate results to demonstrate safe and/or effective human use.
SAFETY
- Not for use during pregnancy or nursing due to pyrrolizidine alkaloid content according to the American Herbal Products Association (ACHS, 2017).
- Oral herbal products containing comfrey are not permitted in the United Kingdom (ACS, 2017).
- The FDA does not recommend oral comfrey products (Natural Standard, 2016).
- According to this in vitro research, topical application of a comfrey root extract has much less toxicity related to limited lycopsamine absorption through the skin. From: Jedlinszki, N., Balázs, B., Csányi, E., & Csupor, D. (2017). Penetration of lycopsamine from a comfrey ointment through human epidermis. Regulatory Toxicology and Pharmacology, 83, 1-4.
- Use of 1 mg or more per day for two weeks can be liver toxic or carcinogenic (Natural Standard, 2016).
- Prolonged use of comfrey of 2mg or more for 2 years or longer could result in liver damage, especially in children (ACHS, 2017).
- Do not apply to broken skin / open wounds due to excessive exposure to the hepatoxic constituent: pyrrolizidine (Natural Standard, 2016).
- Do not confuse with other varieties of comfrey that contain echimidine in the root, a toxic constituent (ACHS, 2017).
- Comfrey leaves look similar to foxglove, which is poisonous.
GENERAL
- ACHS (2017). Course Material: Herb 502. Comfrey Monograph. www.achs.edu
- Natural Standard (2016). Comfrey Monograph. www.naturalstandard.com
ANTI-INFLAMMATORY
- Comfrey extract was anti-inflammatory in humans. From: Petersen, G., Lorkowski, G., Kasper, F. R., Gottwald, R., & Lücker, P. W. (1993). Anti-inflammatory activity of a pyrrolizidine alkaloid-free extract of roots of Symphytum officinale in humans. Planta Medica, 59(S 1), A703-A704.
- Symptoms of swelling, pain, and mobility of ankle distortions was improved with the topical application of a comfrey cream in a study of 203 patients. From: Kučera, M., Barna, M., Horáček, O., Kováriková, J., & Kučera, A. (2004). 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. WMW Wiener Medizinische Wochenschrift, 154(21), 498-507.
- With 142 ankle sprain patients, comfrey applied topically 4 times a day for 8 days was safe and effective in reducing inflammation and pain. From: Koll, R., Buhr, M., Dieter, R., Pabst, H., Predel, H. G., Petrowicz, O., … & Staiger, C. (2004). 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, 11(6), 470-477.
- In a randomized clinical trial of 164 patients with ankle sprains, swelling and pain was improved using a comfrey root extract moreso than a diclo-fenac gel. From: Predel, H. G., Giannetti, B., Koll, R., Bulitta, M., & Staiger, C. (2005). Efficacy of a Comfrey root extract ointment in comparison to a Diclo-fenac gel in the treatment of ankle distortions: Results of an observer-blind, randomized, multicenter study. Phytomedicine, 12(10), 707-714.
- Traumeel is an herbal formulation including Arnica montana, Calendula officinalis, Achillea millefolium, Matricaria chamomilla, Symphytum officinale, Atropa belladonna, Aconitum napellu, Bellis perennis, Hypericum perforatum, Chinacea angustfolia, Echinacea purpurea, Hamamelis virginica, Mercurius solubilis, and Hepar sulfuris. In a review of research, the author concluded that Traumeel is an effective Non-Steroidal Anti-Inflammatory Drugs for treating pain and inflammation, especially related to stomatitis for chemotherapy patients and musculoskeletal injuries. From: Grech, D., Velagala, J., Dembek, D. J., & Tabaac, B. (2018). Critical Literature Review of the Homeopathic Compound Traumeel for Treatment of Inflammation. Pharmacology & Pharmacy, 9(03), 67.
REDUCED PAIN
- In a double blind study, a topical cream containing comfrey, tannic acid, and eucalyptus reduced pain and stiffness associated with osteoarthritis of the knee. From: Smith, D. B., & Jacobson, B. H. (2011). 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. Journal of chiropractic medicine, 10(3), 147-156.
- A double blind randomized study with 120 patients that had acute back pain showed a fast acting reduction in pain with the use of 4 grams three times a day for 5 days of a 35% comfrey root extract ointment. From: Giannetti, B. M., Staiger, C., Bulitta, M., & Predel, H. G. (2010). 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. British journal of sports medicine, 44(9), 637-641.
- An ointment containing comfrey reduced lower back pain with exercise. From: Jurcău, R., & Jurcău, I. (2013). Influence of moderate physical exertion on subacute low back pain, after Symphytum officinale ointment treatment. Palestrica of the Third Millennium Civilization & Sport, 14(3).
- In this randomized double blind placebo controlled trial with 220 patients with osteoarthritis of the knee, a 35% comfrey root extract ointment reduced pain. From: Grube, B., Grünwald, J., Krug, L., & Staiger, C. (2007). 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, 14(1), 2-10.
- Ointments containing comfrey, cayenne pepper, Ledum palustre, and Rhus toxicodendron reduced lower back pain in a double blind multi-center clinical trial of 161 subjects. From: Stam, C., Bonnet, M. S., & van Haselen, R. A. (2001). The efficacy and safety of a homeopathic gel in the treatment of acute low back pain: a multi-centre, randomised, double-blind comparative clinical trial. British Homeopathic Journal, 90(01), 21-28.
SKIN / WOUND
- In a study of 712 children with superficial wound abrasions, a comfrey cream offered an excellent benefit to risk ratio. From: Kucera, A., Barna, M., Holcova, S., Horacek, O., Hladiková, M., & Ottillinger, B. (2018). Tolerability and effectiveness of an antitrauma cream with comfrey herb extract in pediatric use with application on intact and on broken skin. International Journal of Pediatrics and Adolescent Medicine, 5(4), 135-141.
- A topical preparation containing comfrey reduced wound healing time of adults and children without side effects. From: Barna, M., Kucera, A., Hladikova, M., & Kucera, M. (2012). Randomized double-blind study: wound-healing effects of a symphytum herb extract cream (Symphytum× uplandicum Nyman) in Children. Arzneimittelforschung, 62(06), 285-289.
By: Kathy Sadowski
Updated: 5/25/2020
