Comfrey is a plant that grows in Europe, Asia, and parts of North America. It has been used to ease pain and swelling in muscles and joints. It can be used as a gel, extract, or ointment. It can also be taken as a pill or powder.
There are no advised doses for comfrey.
Editorial process and description of evidence categories can be found at EBSCO NAT Editorial Process.
It may be safe to use comfrey for a short time on unbroken skin. It may not be safe to take comfrey orally. Comfrey contains toxic chemicals. Products that contain it have been removed from the market in the United States.D1
Talk to your doctor about any supplements or therapy you would like to use. Some can interfere with treatment or make conditions worse.
A. Ankle Sprain
A1. Koll R, Buhr M, et al. 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 Sep;11(6):470-477.
A2. Predel HG, Giannetti B, 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 Nov;12(10):707-714.
A3. Bleakley CM, McDonough SM, et al. 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.
A4. D'Anchise R, Bulitta M, et al. Comfrey extract ointment in comparison to diclofenac gel in the treatment of acute unilateral ankle sprains (distortions). Arzneimittelforschung. 2007;57(11):712-716.
B. Back Pain
B1. Kucera M, Barna M, et al. Topical symphytum herb concentrate cream against myalgia: a randomized controlled double-blind clinical study. Adv Ther. 2005 Nov-Dec;22(6):681-692.
B2. Giannetti BM, Staiger C, et al. 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 Jul;44(9):637-641.
B3. Pabst H, Schaefer A, et al. 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):811-817.
B4. Oltean H, Robbins C, et al. Herbal medicine for low-back pain. Cochrane Database Syst Rev. 2014;23(12):CD004504.
C. Knee Osteoarthritis
C1. Grube B, Grünwald J, 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 trial. Phytomedicine. 2007 Jan;14(1):2-10.
C2. Laslett LL, Quinn SJ, et al. Treatment with 4Jointz reduces knee pain over 12 weeks of treatment in patients with clinical knee osteoarthritis: a randomised controlled trial. Osteoarthritis Cartilage. 2012 Nov;20(11):1209-1216.
C3. Cameron M, Chrubasik S. Topical herbal therapies for treating osteoarthritis. Cochrane Database Syst Rev. 2013;31(5):CD010538.
D1. Bedi O, Bijjem KRV, et al. Herbal Induced Hepatoprotection and Hepatotoxicity: A Critical Review. Indian J Physiol Pharmacol. 2016 Jna-Mar;60(1):6-21.
E. Wound Healing
E1. Barna M, Kucera A, et al. Randomized double-blind study: wound-healing effects of a Symphytum herb extract cream (Symphytum×uplandicum Nyman) in children. Arzneimittelforschung. 2012 Jun;62(6):285-289.
Last reviewed February 2020 by EBSCO NAT Review Board Eric Hurwitz, DC Last Updated: 6/22/2020