Comfrey has a long history as a healing herb going back to the times of the Romans. It’s a plant of many talents, traditionally used for everything from a super-charged nitrogen-fixing fertilizer, to broken bone setting “plaster” to an effective stamp glue substitute. The name comfrey comes from the Latin con firma, “with strength” and symphytum (Symphytum officinale) is derived from the Greek symphytos, “to unite.”
A couple of comfrey’s many folk names, “knitbone” and “boneset,” really say it all. Comfrey leaves and particularly the root contain allantoin, a cell proliferant that increases the healing of wounds. It’s also soothing, stops bleeding and is one of the most popular ingredients in herbal skin sales for wounds, inflammation, rashes, varicose veins, hemorrhoids and just about any skin problem. Taken internally, comfrey repairs the digestive tract lining, helping to heal peptic and duodenal ulcers and colitis. Studies show it inhibits prostaglandins, which cause inflammation of the stomach lining.
In recent years, comfrey has also developed a rather unfortunate reputation as a controversial herb, thanks to some studies run on one of its constituents, pyrrolizidine alkaloids. One of the (many) problems with these studies, is they involve labs animals injected with isolated PAs at levels far greater than any person could realistically consume in real life. In another study, rats fed a comfrey diet (up to 33%) developed liver cancer. So far, only two cases of possible comfrey poisoning have been reported in people. Once was a 13- year-old British boy who ate comfrey regularly for about 3 years, but the researchers admitted that he might have been more susceptible because of an underlying inflammatory bowel disease.
If you are concerned about toxicity issues and comfrey, consider that there are over 200 types of PAs occurring in about 3% of the world’s plants, including comfrey. The fresh root contains approximately 10 times more pyrrolizidine alkaloids than fresh leaves. The amount of PA in fresh, young spring leaves average only 0.22%, and even less in young fall leaves (0.05%) Mature leaves contain only 0.003%. Two investigations found 0.0% present in the leaves of dried comfrey.
Of course, do your own research, but a large body of traditional use spanning thousands of years supports comfrey’s safety and efficacy. On that note, here’s a tried and true recipe for comfrey & bacon from The Wild Foods Cookbook that’s just as good as it sounds! ??