What Is Comfrey Used for Today?
- Do not apply comfrey for more than 4-6 weeks per year.
- Do not use for more than 10 days in a row.
- Do not apply to broken skin.
1 Koll R, Buhr M, Dieter R 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;11:470–7.
2 Kucera M, Barna M, Horacek O, et al. 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 MedWochenschr . 2005;154:498–507.
3 Traumaplant® Cream: the percutaneous antitraumatic. Available at: http://www.harraspharma.de/framework%5Fe.html?/html%5Fmedika/traumaplant%5Fexp%5Fe.html . Accessed June 9, 2005.
4 Oberlies NH, Kim NC, Brine DR, et al. Analysis of herbal teas made from the leaves of comfrey ( Symphytumofficinale ): reduction of N-oxides results in order of magnitude increases in the measurable concentration of pyrrolizidine alkaloids. Public Health Nutr . 2004;7:919–24.
5 Williams L, Chou MW, Yan J, et al. Toxicokinetics of riddelliine, a carcinogenic pyrrolizidine alkaloid, and metabolites in rats and mice. Toxicol Appl Pharmacol . 2002;182:98–104.
6 Mei N, Guo L, Fu PP, et al. Mutagenicity of comfrey ( Symphytum officinale ) in rat liver. Br J Cancer . 2005;92:873–5.
7 Stickel F, Seitz HK. The efficacy and safety of comfrey. Public Health Nutr . 2000;3:501–8.
8 Couet CE, Crews C, Hanley AB. Analysis, separation, and bioassay of pyrrolizidine alkaloids from comfrey ( Symphytum officinale ). Nat Toxins . 1996;4:163–7.
9 Winship KA. Toxicity of comfrey. Adverse Drug React Toxicol Rev . 1991;10:47–59.
10 Betz JM, Eppley RM, Taylor WC, et al. Determination of pyrrolizidine alkaloids in commercial comfrey products ( Symphytum sp.). J Pharm Sci . 1994;83:649–53.
11 Yeong ML, Wakefield SJ, Ford HC. Hepatocyte membrane injury and bleb formation following low dose comfrey toxicity in rats. Int J Exp Pathol . 1993;74:211–7.
12 Yeong ML, Clark SP, Waring JM, et al. The effects of comfrey derived pyrrolizidine alkaloids on rat liver. Pathology . 1991;23:35–8.
13 Kucera M, Barna M, Horacek O et al. Topical symphytum herb concentrate cream against myalgia: a randomized controlled double-blind clinical study. Adv Ther. 2005;22:681-92.
14 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 trial. Phytomedicine . 2006 Dec 12 [Epub ahead of print].
15 Barna M, Kucera A, Hladicova M, et al. 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;157:569-574.
16 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.
17 Oltean H, Robbins C, et al. Herbal medicine for low-back pain. Cochrane Database Syst Rev. 2014;12:CD004504.
- Reviewer: EBSCO CAM Review Board
- Review Date: 09/2014 -
- Update Date: 03/19/2015 -