I got into a “discussion” on a forum recently on the use of Comfrey Symphytum officinale. One woman whom I do not know nor know her qualifications, stated that the “scare” over the use of comfrey is another attempt by Big Pharma to malign the use of herbs in a medicinal context.
You will rarely hear me defend Big Pharma but this time they’re not the culprit. The “scare” is somewhat justified. While comfrey has been used for centuries to heal sprains, strains and broken bones (one of its common names is “Knitbone”) and for some lung problems, studies conducted since the 1980’s have shown that comfrey contains pyrrolizidine alkaloids (PAs) – some of which can be toxic to the liver or cause cancer.
As Henriette says, in many, if not most cases you don’t know you have liver damage until it’s too late. Yes, comfrey has been used for ages but we don’t know what folks died of – no autopsies were done to tell if their death was caused by cirrhosis of the liver.
I don’t have access to all the research papers mentioned in PubMed to tell whether the trials were done with a tea made from the leaf or root, or other preparation; what dosage was used; and how long the trials continued but I DO know that products containing herbs that have PAs, such as comfrey, are banned in Canada and very closely regulated in Germany (where herbal medicine is quite accepted).
A problem here in the US is that the commercial products sold containing comfrey don’t tell you which comfrey you’re getting – common S. officinale or Russian S. x uplandicum. Russian comfrey contains more PAs than common comfrey.
Comfrey root contains up to 29% mucilage, making it good for treating lung problems, such as bronchitis or whooping cough. Both the root and the leaves contain a goodly amount of allantoin, which speeds up the replacement of body cells. This explains why it helps heal sprains and broken bones.
I like my liver healthy, thank you, so I prefer to err on the side of caution. If there’s another herb that will work as well as comfrey, I’ll use it. The one time I got a bad case of bronchitis, I didn’t have any marshmallow root in stock, so I made a tea from dried comfrey root (from my garden so I know which comfrey it is) and took it for one week only. Because I’m a klutz, I keep the dried leaf on hand. This I use to make a poultice for the occasional strain or sprain (or <fingers crossed, knock on wood> a broken bone) and I only use it externally and never on broken skin. The PA’s can be absorbed into your system through an open wound. Not to mention that, just like Calendula, it heals wounds so quickly that the skin could heal over an infection, creating even more problems.
I do keep the dried root on hand for other things … it’s great in spells for travel and money. Whenever I fly, I tuck a piece of root in my suitcase. The airlines haven’t lost my luggage, yet. 🙂