Is comfrey (Symphytum species) honey toxic to people?

[susan rudnicki]

Someone submitted a question regarding the toxicity of honey from nectar gathered from the herb, comfrey, (Symphytum species) as there is some evidence it can be a toxic plant if ingested. Here is a note from Wikipedia regarding the properties of this plant. Unlikely the honey is at all a issue. Read closely—the common names of plants do not always distinguish between different species, so the issues are not all equal.

In modern herbalism, comfrey is most commonly used topically. Some experts say that comfrey should be restricted to topical use, and should never be ingested, as it contains dangerous amounts of hepatotoxic pyrrolizidine alkaloids (PAs).[18][19] Studies associating comfrey with veno-occlusive disease (VOD), do not differentiate between Russian and common comfrey, plants with very different levels of PAs. VOD can in turn lead to liver failure, and comfrey has been implicated in at least one death, though the type of comfrey being consumed, and other dietary, physiological and pharmacodynamic factors were not accounted for.[20] In 2001, the United States Food and Drug Administration issued a ban of comfrey products marketed for internal use, and a warning label for those intended for external use.[21][22] In addition to restrictions on oral use, some experts recommend applying comfrey extracts no longer than 10 days in a row, and no more than 4–6 weeks a year.[16][23]

[Daniel Dioguardi]

Thank you. I have also recently seen a study on herb toxicity called “Safety issues affecting herbs: Pyrrolizidine Alkaloids” published by Subhuti Dharmananda, PhD, Institute for Traditional Medicine , Portland, Oregon. This report says that PAs can get into honey, but there have been no documented reports of liver failure due to PAs in honey (referenced in paper).

[susan rudnicki]

I perused this article mentioned and the listing of plant families identified as sources of the pyrrolizidine alkaloids. The thing is, I know that MANY of these plants are also used by honey bees extensively for nectar and pollen—the Boraginaceae family and the Asteraceae. One could argue that poisons from the honey made from these sources “caused” a liver breakdown, but we are also surrounded by so many PCB’s, outgassing plastics, resins, textiles, and food packaging products, and myriad chemicals from air, water and soil, that I find the attribution of a malady from one particular insult pretty difficult to assign.

[Daniel Dioguardi]

I agree.. in the end, it’s probably no more harmful than a bottle of my favorite beer… Which I happen to be enjoying right now. So I’ll not worry about the comfrey in my field. Thank you

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