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.
Kucera M, Barna M, Horacek O, et al. Efficacy and safety of topically applied
herb extract cream in the treatment of ankle distortion: results of a randomized controlled clinical double blind study.
Wien MedWochenschr. 2005;154:498–507.
Traumaplant® Cream: the percutaneous antitraumatic. Available at:
http://www.harraspharma.de/framework_e.html?/html_medika/tra...plant_exp_e.html. Accessed June 9, 2005.
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.
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.
Mei N, Guo L, Fu PP, et al. Mutagenicity of comfrey (
Symphytum officinale) in rat liver.
Br J Cancer. 2005;92:873–5.
Stickel F, Seitz HK. The efficacy and safety of comfrey.
Public Health Nutr. 2000;3:501–8.
Couet CE, Crews C, Hanley AB. Analysis, separation, and bioassay of pyrrolizidine alkaloids from comfrey (
Nat Toxins. 1996;4:163–7.
Winship KA. Toxicity of comfrey.
Adverse Drug React Toxicol Rev. 1991;10:47–59.
Betz JM, Eppley RM, Taylor WC, et al. Determination of pyrrolizidine alkaloids in commercial comfrey products (
J Pharm Sci. 1994;83:649–53.
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.
Yeong ML, Clark SP, Waring JM, et al. The effects of comfrey derived pyrrolizidine alkaloids on rat liver.
Kucera M, Barna M, Horacek O et al. Topical symphytum herb concentrate cream against myalgia: a randomized controlled double-blind clinical study.
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].
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.
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.