Comfrey (Symphytum officinalis)

Botanical Medicine: Comfrey, Coltsfoot & Pyrrolizidine Alkaloids

Is Symphytum officinale (Comfrey) safe for internal use? And what about Tussilago farfara (Coltsfoot)? Maybe not, according to clinical cases published in the last few years which suggest that the pyrrolizidine alkaloids in these popular traditional herbal medicines may cause serious liver disease if consumed over long periods of time. Germany recently banned some 2500 herbal products with pyrrolizidine alkaloid content, because of these and other cases. Canada recently also banned comfrey root and coltsfoot.

Comfrey Root Ointment Reduces Pain in Patients with Knee Osteoarthritis

Reviewed: Grube B, Grunwald J, Krug L, 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, place-bocontrolled trial. Phytomed. 2007;14( 1):2-10.


Comfrey (Symphytum spp.), long one of the most popular herbs in European folk medicine, has become increasingly controversial because of reports that it is toxic to the liver, and perhaps carcinogenic. At issue is a class of chemicals called pyrrolizidine alkaloids (PAs). Alkaloids of this type are responsible for the toxicity of such poisonous plants as Heliotropium, Crotalaria, and Senecio. They have caused substantial losses of grazing livestock, and some human poisonings as well.

Comfrey is Comfrey is Comfrey: or is it?

Summary: The pyrrolizidine content of thirteen commercial Comfrey products sold in Canada was examined due to concern about its safety. The samples were representative of the variety of sources, shapes, and forms of commercially available products. Echimidine which is probably the most toxic PA of Symphytum spp. was detected in nine of the thirteen samples. Chemotaxonomic studies have indicated echimidine is often not found in Symphytum officinale and when it is, the PA is in low levels. High levels of echimidine are regarded as a strong indicator of non-Symphytum offinale origin.

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