Saturday, April 4, 2009

Comfrey: Wonder Plant

I rarely cheerlead for products or services, and I don't think I've ever promoted a particular plant before. But today I'm going to discuss the many merits of comfrey, because it's both extremely valuable in the home garden and also little known.

Comfrey is an herb native to wide swaths of Europe, long known for its soothing medicinal properties. Many over-the-counter skin ointments and homeopathic products include this herb for its healing qualities. One of the effects of comfrey when applied topically is to increase the rate of cell division, so that wounds and burns heal more quickly. A woman in my area posted an advertisement last year looking for fresh comfrey. She had a skin condition that hadn't responded to any treatment she had tried. She used some of my Bocking 14 comfrey to make a tea that she soaked her arms in and later told me that the comfrey helped more than anything else had. She just sent me an email asking if my comfrey had any leaves up yet this year. Comfrey also reduces inflammation, swelling, and irritation. If you enjoy home remedies or making herbal salves, comfrey would be an excellent addition to your garden.

There's an ongoing debate as to whether or not comfrey can be safely consumed, even by animals. There is apparently some level of toxicity for the liver, both in humans and in animals. I am definitely not recommending that anyone consume any part of the comfrey plant. However, some studies suggest that a toxic dosage would only be reached after consuming huge quantities of the leaf or root. Comfrey is very widely used in Japan as an animal fodder, without any ill effects, evidently. And I have spoken to several homesteaders who regularly give small quantities of comfrey leaf to their chicken or duck flocks and even to pigs. I myself have fed my laying hens comfrey leaf about once a month in modest quantities. The chickens absolutely relished the stuff. Since comfrey leaves are very high in protein, this isn't surprising. I never observed any detrimental effect on the hens after feeding them comfrey leaves.

But comfrey has yet other virtues beyond healing and animal fodder. Comfrey is a bioaccumulator plant whose long roots mine minerals and nutrients from very deep in the soil. (There are reports of comfrey roots reaching as much as ten feet deep into the ground!) Other culinary and medicinal herbs grown adjacent to comfrey have been observed to contain higher levels of essential oils and flavor than herbs of the same type not grown next to comfrey. Comfrey leaves can be cut and used as excellent green manures for other garden vegetables. The first leaves put out by comfrey plants each spring were traditionally used specifically with the planting of potatoes, to give the potato plants an early boost of nutrition and growth.

Comfrey is particularly known as an excellent companion plant in fruit orchards, especially apple orchards. With its tall and densely growing leaves, it will easily outcompete other nearby plants, reducing the need for weeding. Though it likes full sun, it can also tolerate the shade under fully grown trees. This contributes to its utility in orchards.

Although comfrey will not spread aggressively if left undisturbed, it is quite tenacious once it is established. And if the earth around it is tilled, new plants will grow from broken off fragments of root. If you want to eradicate comfrey from a particular spot, it will likely take some doing. So choose a spot to plant it with care. I have heard tales of gardeners cutting comfrey to use as green manure when planting other crops, only to find that the cut leaf took root and established itself in the new location. I haven't seen this happen [Update: I have seen this happen.], but then I take the precaution of letting all comfrey cuttings intended for green manure wilt in the sun for a few hours after cutting.

Along with its utility as a green manure, comfrey is equally valuable as a foliar feed ingredient. Foliar feeding is a natural form of fertilizing that uses weeds or other plants in a fermented liquid state. Like all anaerobic fermentation, a foliar feed made from comfrey leaves will smell atrocious. But it produces a natural, concentrated liquid fertilizer that can be diluted and applied to the leaves of many vegetable and flowers.

The comfrey varieties I have planted have large, somewhat oval, slightly hairy leaves that grow up to about 30" tall. Near the base of the leaf stalk the hairs sometimes develop enough heft that they become small prickles, much like a summer squash vine will produce. But they are not particularly bothersome. In their second year comfrey plants put out borage-like flowers for a long time from late spring to to late summer. They vary in color apparently, but my plants' flowers are purple. Most varieties of comfrey do not reproduce themselves well from seed, but will readily grow from root divisions. There are several varieties of comfrey, all of them fairly hardy perennials. Some varieties are hardy up to zone 3, but most are hardy to zone 4 or 5. The Bocking 4 variety was specifically developed as a green manure, while the Bocking 14 was developed as animal fodder.

This is such a useful plant that I recently ordered a third variety, common comfrey, and plan to divide the roots of each type of comfrey I grew last year. It will allow me to make good use of the shaded areas of my property where very few edible things will grow. Instead, I'll harvest the fertility of those spots and transport it to my garden beds in the form of comfrey leaves. I can scarcely credit so many wonderful qualities packed into this one plant. Comfrey has medicinal uses, can feed livestock, and greatly enhances the fertility of my garden soil. On top of that, it's an attractive plant that has few pests and provides a bit of food for bumble bees. I can hardly think of a non-edible plant that I would consider so essential for a sustainable garden as comfrey.

If the long term fertility and health of your garden soils are of concern to you, look into comfrey! I got my comfrey plants last year from Richters. They have an amazing selection of herb seedlings, and the prices aren't too bad. I only wish I'd ordered some of the intriguing Piss-Off plant!

Update: check out what I learned at the 2010 PASA conference for yet another awesome attribute of comfrey. Just when I thought this plant couldn't be any more impressive, I found out I was wrong.

51 comments:

willywagtail said...

I haven't had comfrey in any garden for a few years but I swear by the brown ointment for healing. You are not meant to put it directly on open wounds but I always lather it on bleeding areas and it iworks like a miracle healer. I have had no ill effects. Cherrie

Red Fern said...

Thanks for giving me another must have for my herbal collection! I really like the idea of feeding comfrey to the hens occasionally.

Becca's Dirt said...

Comfrey is new to me. Good info. This is my first visit to your blog. Thanks for that useful information.

Kate said...

Thanks, all, for stopping by and leaving a note here. Red Fern and Becca, I'm glad I could teach you a bit about a new useful plant.

I am becoming more and more interested in herbs as I try to find ways of utilizing shaded parts of our property. Perhaps a few posts on herbs are in my future.

onestraw said...

When I first planted Comfrey a few years back my mother was shocked to see it - turns out the local women had wrapped her knees with it after she took a bad fall on a snowmobile in the 1950's. It was also widely used in the Civil War as a bandage, earning the name Wound Wort.

I can get 5 cuttings a year off mine in Zone 5b and grew the best peppers of my life in a bed of mulched comfrey last season. One of my all time favorite plants.

Kate said...

Onestraw, I love that image of comfrey leaves as bandages unto themselves! They're certainly big enough. I didn't cut much last year. I figured I'd mostly let them grow undisturbed their first year. Will definitely cut more off those plants this year, while letting the new ones get established, especially since the new ones will be in partial shade.

ChristyACB said...

Great post on one of my favorite plants! I have 2 biggies growing and those will be ready for hearty division for next year when the season ends.

Many people are put off by the idea of the deep roots and difficulty in eradication. They look at the various other invasives and just can't bear another developing. Since I'll be moving to my homestead from my wetlands home in a few years, I've been keeping mine in GIANT pots. while they can't root too deeply, they grow quite well.

Medicinally, they are the best! I've used it for humans and animals (cut pads on a dog) and the tea is quite soothing on skin with rashes and the like.

Super post, love the blog and hope to see more articles on plants like this one.

Kate said...

Christy, thanks for stopping by. I don't know that I'll have a lot more posts on individual plants. I'm far from an expert. But I just felt the need to gush a little bit about comfrey because it is so very remarkable. I'm itching to make some divisions this year too. Thanks for letting me know it will grow in pots. Someone had asked me about that and I was doubtful because of what I'd heard about their tap roots. Good to know they manage alright in a pot.

Jim said...

Thank you so much for your post on comfrey. I will try to find some cutting on Craigslist and plant some in my garden. I can use a plant like this. If anyone happens to have a couple cuttings can you please contact me? I have a very new 3/4 acre plot that needs the help of this plant. Sounds like the hens will like it too.

Thanks again for your notes,

Jim L.

Kate said...

Jim, you're quite welcome for the post. Thanks for letting me know it was useful to you.

You probably won't have much luck finding offers for a seedling in this comment section. Few people will read your request, and then your profile is no publicly shared, so we don't know where you are. You might consider posting on your local craigslist site to find a gardener near you.

Anonymous said...

Comfrey is taking over my suburban
garden. No matter what I do ... it
spreads. I cut it, it's back to new
in weeks. I have no idea how to control it.

I'd like to live in harmony with comfrey.I know it's a good plant, that is why it was planted and our bees love it.

Any ideas on controling it's spread without having to do complete eradication ??

Patty

Kate said...

Patty, it's a tough situation. I hate to say this, but if you don't want to go with complete eradication (which would be difficult to accomplish), you're probably going to have to be the one that changes, rather than the comfrey plant. I know adjusting one's attitude to see something as an asset rather than a problem is not easy.

Beyond the attitude adjustment, I would recommend that you simply plan to cut the comfrey back severely several times during the growing season. If it's a well established plant, it can take it. Spread the cut branches out around your garden to shrivel in the sun. DO NOT bury freshly cut leaves or branches from the plant as they may take root wherever you put them. Just think of the comfrey as green mulch, and try to make your peace with it. Either that, or you may need to declare all out war.

Good luck!

Cheryl Anderson said...

I have heard comfry can replace Horse manure in Manure / COmpost tea for those who are against animal manure usage... Have to be careful. Some have mistakened foxglove, which is poisonous, for comfrey... So make sure it is comfrey... I have comfrey. The place I got it from gave it to their customers thats cows had skin problems... My chickens are around it and have foraged it no problem. They don't eat much, but it is there if they want it.

Anonymous said...

i'm looking for comfrey bocking 14 plants for spring and i live in southeastern pa also, would you be willing to trade something?

Kate said...

Cheryl, I can see the resemblance between foxglove leaves and comfrey leaves, but the differences are pretty pronounced as well, even if the flowering parts of the plant are ignored. Foxglove leaves are soft and velvety, while comfrey leaves have small, slightly irritating prickles on them, especially as they get bigger. In any case, this is part of the reason for not recommending that any part of the comfrey plant be consumed. BTW, I know of a Cheryl Anderson in SE PA, though I'm not entirely sure of the spelling of the first name. Are you in this area? If so, you might know my aunt.

Anon, certainly I'd be willing to trade/barter for some of my bocking 14. Please leave your email address in the comments so I may contact you. I can delete the comment with this information as soon as I have it. Thanks for the offer.

Jim said...

Kate,

Thought you might like an update on my garden. We put in comfrey about 2-3 months back I guess. It is doing great. The hens love it.

Thanks again for your page.

Kate said...

Jim, thanks for stopping by with the update. I'm glad you found some comfrey and are pleased with it. It's a good plant to have around any garden or homestead.

Anonymous said...
This comment has been removed by a blog administrator.
Cheryl Anderson (SwineInsanity) said...

I live in Puget SOund Washington... I also have stinging nettle in my garden which can be used in compost tea, is good tea for allergies since it is a antihistmine, and from what BackYard Poultry said, it is good for chickens! BTW, Awesome blog. Found you through the blog Homesteading in Maine. :)

Kate said...

Cheryl, thanks and I'm glad you found your way here. I may try growing stinging nettle again next year. I've enjoyed eating it in the past, but couldn't get it to grow this year. Always something for next year, and yes, I've heard great reports of it helping with allergies.

Cheryl (SwineInsanity) said...

I found it grows best by fenses... I have mine growing on my southern side of the house right next to my veggie garden... How I found out of its use is in James Dukes book the Green Pharmacy... I highly recommend it...

Lynda said...

I'm hoping someone here can help me. I just received my comfrey root in the mail and there are no planting instructions with it. Do I plant it now? I live in Illinois and it's going to be pretty cold here soon. Do I save it until Spring and,if so,how should I store it? Any advice would be much appreciated!

Jim said...

Hi Lynda,
About your planting comfrey at this time of year… If you only have a small amount I would consider planting them in pots and keeping them outside as long as you can. Then bring them in when it gets to cold out. I'm in Southern California and don't have much experience in cold areas. That said, mine have grown like crazy. If you planted them now I would bet they will take root before it gets real cold. Then when the leaves drop or wilt, I'd cut them back and mulch heavy with straw. The things are tough as nails I bet you will be fine. Let me know come spring how
things turn out?
Jim L

Kate said...

Lynda, I think I'd agree with Jim here, though I grew my plants out from starts, not roots. In my experience, comfrey is nigh on indestructible. If it has any chance *at all* it will grow and thrive. You could try it out in the ground or in a pot. Just be sure the spot you pick is where you're going to want it.

And Jim, thanks for chiming in.

Jim said...

Just a note for anyone that cares to read it. I planted 12 bare root plants in mid July. I bought them mainly for the hens we have (4). Comfrey is everything I could have hoped for! Right now I pick 12 large leaves a day for the birds. One from each plant. The darn things can keep up with that type of abuse! The "plants" not the birds. By the way the birds start hopping when I get out the clippers to cut leaves in the morning. They love it.
All I have done is water them with a drip system and side dress them with horse manure once when they got to about 14 inches tall. They seemed to get a boost from the horse dung (aged, not hot). Also of note I cut my left forefinger real bad working with a utility knife. Took out a nerve. I put a comfrey poultice on it for the first two nights and that was it. Inside of a week there was nearly no scarring! I have never had a wound heal that fast. This was obviously a deep cut. I was truly amazed. Absolutely no other care but two nights of comfrey! Wow!

Thanks Kate for inspiring me to plant THE wonder plant. Pigeon Peas are fun too. Anyone want to talk about them? I'd like to hear your experiences... with them.

Jim L.

Kate said...

Jim, you've done more for your comfrey than I've ever thought about doing for mine. I wouldn't dare feed mine for fear it would take over the world. I've been feeding our new girls more comfrey lately too. Incidentally, I have now seen comfrey take root from cut leaves with absolutely no encouragement and only the barest odds. I'm now rather cautious about it and won't bury it at all after cutting until it's been exposed to the elements enough to be properly killed.

Jim said...

Wow Kate!,

I had know idea I could propagate it form just a cut leaf! I need/want more a lot more. You see my buddy has sort of given us 16 more hens. I need the feed. I'll start some cutting today and see what comes of it. I'll keep you posted. Mind are fast growers but because I cut them so much they never get much of a chance to get "real" big. Heck I could use it for green manure too at that rate. Guess I need to put my head up from weeding and start paying attention to stuff I should have already thought about. I was thinking about taking a plant and dividing the root system. Dahhh! I should have been thinking a cutting. Thanks for the "heads up". Wewh hew more comfrey coming up!

Jim L.

Kate said...

Jim, I still have no idea what part of the world you're in. Keep in mind that when the days are short, nothing much will grow. So you may not see the comfrey take root at this time of year if you're in the northern hemisphere. I don't put very much past comfrey, but rooting from a cutting this time of year would impress even me.

I've seen leaves with a bit of stem attached take root when lightly buried in loosened soil, even when the covering is just mulch. We get plenty of rainfall here, so that probably helps. It's a little frightening to see how easily propagated this stuff is. Fortunately, when I've plucked the newly formed plants out from where they weren't wanted, that took care of the problem. Much as I admire the plant, I don't want my garden overrun with the stuff.

Jim said...

Thanks for the advice Kate. FYI I'm in Southern California. My comfrey only grows where I give it water so far. This area is still by definition a desert. I will try to put in some starts maybe next weekend. I'll keep you posted. Heck I still have corn coming on!

JL

Kate said...

Jim, southernmost CA never dips below ten hours of daylight, even at the solstice. If you're that far south, or even near enough, you can probably get comfrey to take root any time of year, even if very slowly.

We lose our ten hours of daylight on November 11th, and don't get it back until February 2nd. And if you've read Eliot Coleman, you know that 10 hours is the magic number for plant growth.

Jayme, The Coop Keeper said...

I came across your blog googling comfrey! Love it! I'm wondering if you would be able to answer a question. I have a gorgeous four foot tall patch of comfrey. This is the largest it's gotten since I planted it years ago. It's up against my house, and with some high winds today, it's laying on it's side. Now - I wouldn't give a hoot - but in a month I'm going to be on a garden walk, and I'd like it to look nice. I'm wondering if I cut it back, will it grow back out in time for the Garden Walk? Hmmmm.....

Kate said...

Jayme, it's a good question. I don't have the answer for certain, but I'm kinda in the same boat with you. One of the comfrey plants in the garden has keeled over and half buried some kale. So I'm going to cut it back severely to give the kale a chance. I'm fairly confident it'll grow back just fine. But I don't know how quickly (though I doubt it'll take very long this time of year). I suppose it's an experiment for another post!

Jim said...

Hi Jayme,

If you care for my answer... My guess is that it won't pop back in a month. It I'm sure would have some little leaves but wouldn't be filled out much.

Just my guess,

Jim L.

JDon Corely said...

Too often, researchers haveon both sides of the comfrey usage debate have failed to distinguish WHICH variety of comfrey being was being researched, at a given time. The pyrrhizoladine content in comfrey varies SIGNIFICANTLY between American Comfrey and its European counterpart- the latter having higher concentration of the potentially cancer causing substance, in rats (and possibly humans). American Comfrey is used grown at the George Washington Carver Botanical Garden in South Jamaica, Queens; and it is used for teas, tinctures, and in sparing amounts, for food. As a teen, I used it in extract from to boost energy (owing in part to its high chlorophyll and general mineral content) and to treat excema, with much success.

Jim said...

JDon Corely,
I use Blocking 14 for my hens and compost. Do you know the origins of it?

Jim

salviadorii said...

Hope this isn't bad blog comment etiquette but I have been searching for someone with extra Bocking 14 comfrey cuttings or root chunks.When I read this discussion on comfrey and saw that Jim was fairly close by I thought well I just have to try.I am up in the desert on the eastside of the Sierra in Ca.and would love to somehow find out if Jim might have some cuttings or root chunks.Now how to get in touch.ok,thanks

Kate said...

Salvia, I have no objections, but also no idea whether Jim subscribed to comments on this post. If you can't scare up a donation from anyone local, I recommend you patronize Richter's Herbs in Canada. The quality of the plants they ship has always been outstanding.

Jim said...

Hi,

Salvidori and Kate,

At this time I am unable to spare any. I just divided mine for a much larger crop. We have tripled our hen population and need the forage and green manure. I LOVE this plant. I pretty well brutalized the roots to divide them and replanted them. I fear that further cutting and disrupting them up will result in failure. Kate, if you could arrange a private email exchange between the two of us I can stay in touch and eventually get some extra. I'd rather not have my email out there for the world to see. Not worried about the posters here but others... Hope you understand.

Jim

Jim

Kate said...

Here's what seems easiest to me. I don't have access to email addresses of commenters. Salvia, Jim has obviously subscribed to this comment section. Since you are the one who requested contact, leave your email or whatever contact information you want in a comment here. It'll be sent automatically to Jim. As soon as I see it, I'll delete your comment, so it won't be visible on this page. It's an old page anyway, so I doubt it'll get much traffic.

salviadorii said...
This comment has been removed by a blog administrator.
Jim said...

Thanks Kate,

Jim

Anonymous said...

I'm getting my first comfrey plants this weekend. After reading all these posts I'm going to assume its the bock 14 plants since it can be used on animals. I'm very interested in the medical aspect of using this plant. For the healing and such...and how to go about "harvesting it" for such. ANY help, advice is much appreciated. So glad to hear that its a hardy plant...since I tend to kill everything! LOL

Kate said...

Anon, well, if you visit my front page you will quickly deduce that some of the best advice on comfrey is to choose where you plant it very, very carefully. Once it's in, it will be a real battle if you ever want to get it out. Other than that, I suggest you get one of the varieties that produces sterile seed. Those will expand to a certain point and not beyond, and will not rampantly reproduce themselves without intervention. Other than that, give it one year to establish itself before you cut it. You can take a few leaves in the summer and fall of the first year, but wait until year two for drastic cuttings. From then on you will be able to take at least two full cuttings every year, and more if your plant is in good soil. I harvest with a hand scythe, wearing gloves. As the plant gets large each year, it becomes rather prickly. Early spring cuttings can be done bare-handed. Do not clean it up in the fall, but let the leaves die down and lie on the ground. Clean them up in spring and use them as a good mulch for another plant, or add to the compost.

Morvan said...

Hi,
I live in France.
I am looking for comfrey roots or plants of comfrey bocking 4
In your article you speak about Richters.
They did not have more of comfrey roots of bocking 4
See http://www.richters.com/Web_store/web_store.cgi?product=X1876&show=all&prodclass=&cart_id=4452717.4841
Do you know somebody who sells bocking 4 roots?
Excuse me for my poor english
Maxime Morvan
Concarneau France
max.morvan@free.fr

Anonymous said...

I make a fantastic drink using fresh comfrey leaves minus the rib, pineapple juice, a bunch of parsley and after it has liquified I add a banana. Very tasty and healing.

Anonymous said...

Glad to see so many positive comments on comfrey as there has been so much ridiculous slander of this wonder plant over the years. I've read scientific studies that prove it is not harmful. It is excellent to feed your farm animals. and to eat yourself. I've been eating it regularly for 30 years and always use it as a fantastic healing ointment or poultice. i've always said it is a first Aid kit in a jar and the most important plant in anyone's garden.It is full of nutrition and beneficial minerals. Potassium, calcium, allantoin. It speeds up skin repair, will prevent bruising if put straight on to a fresh wound, and is the best ointment to put straight on to burns or sunburn. The tincture is brilliant for broken burns, and it was called knit bone. It heals ulcers too.

marco said...

Very interesting. My late mother started the plant out back by the garage. It was for its healing properties, but I never paid much attention. Now I will because I have a recurring skin rash of some type. I learned some things reading all of the story and posts. I live in Northern Maine.

stern said...

comfrey varies SIGNIFICANTLY between American Comfrey and its European counterpart- the latter having higher concentration of the potentially cancer causing substance,any documentaion on this ???all i knew were about liver toxicity ??

magic wizard said...

Comfrey is one of the best things you can grow in your garden if you are into the natural healing. As a Holistic Practitioner I used it in my practice for 17 years including on myself when I had a personal injury. I grew the plant in my small tiny patio and nothing could kill that baby, they are hardy plants and they will spread. I broke both my wrists at the same time when I had an ugly fall years ago. If you could just imagine what that means... it's not pretty. I has at that time a 12 year old son, and a business to run as a self employed individual, without my hands.... no $$$ come in and no disability benefits. Western medicine of course,... casted both my hands all the way to 4" below the elbow., well. this does not give you a lot of mobility now, does it, so by the time I got home, between my good friend and my son, we proceeded to remove both casts, (never try this at home) and started a 2 week healing process with Fresh Comfrey. My friend helped me (or did) chop 3 to 4 large leaves of Comfrey (chop like parsley) , couple of Lavender stems + flowers, couple of Chamomile stems + flowers and mix this with Castor Oil, Arnica, cayenne Pepper oils and made a pulp that was applied 1 x's per day, wrapped and a heating pad on for 15 minutes. The mixture stayed on for about 4 hours (I do not recommend making this mixture unless you really know what measurements to use, this recipe was given to me by my father and goes back to 1938). To end the story, I had a doctors appt. 2 weeks from that day and when I went he was extremely upset at me removing the casts and made me sign a waver that I wouldn't hold him responsible for damage. After taking the xray there was no sign of what he called an "open break" in either of my wrists and wanted to know what magic I had done, he couldn't believe it and even asked me for the recipe (which I just smiled), so Thanks dad for all the wonderful information you left me with that to this date I I use.

Anonymous said...

As a 10 year old girl my Mom had a severe leg bruise that somehow got infected. When she was taken to the doctor they were going to remove her leg. My grandpa used comfrey on her leg several times a day and after several weeks the leg was as good as new. she was taken back to the doctor just to show him how wrong he was. If it were not for comfrey she would have lost her leg.

Anonymous said...

Hi, this explains a little more about the "cancer scare." I'm definitely not afraid of it and would even take the root (has the most alantoin) in a heartbeat. The comments came from a Susan Weed forum.

Judith Berger's very sound and grounded discussion of Comfrey in Herbal Rituals is what put all my fears to rest about this herb. She goes over all the major info from the scientific community that caused the scare, and shows how contradictory much of it is. She also talks about the herbalist Adele Dawson "who firmly stated that she attributed her good health to drinking a single cup of comfrey leaf tea each day for thirty years".
I checked into this a number of times and found a pretty elaborate description (online somewhere, I THINK the original research came out of Australia? Not sure) that has for years fueled my 'answer' which is that the 'research' that kicked off this whole "Comfrey Causes Liver Cancer" nonsense was just plain lousy science. In their efforts to PROVE that Comfrey was harmful, the pyrrolizidine alkaloid was first extracted from every other constituent of the plant (lost me right there) then they SYNTHESIZED that alkaloid (that's another distortion) and then they fed it to the hapless rats at something like NINE TIMES their body weight. Helllooooooo. And with all that, those poor rats only showed CHANGES in their livers, not cancer at all. Susan herself got sufficiently aggravated that she sent five mature Comfrey leaves to five different labs for analysis and every one came back as having NO pyrrolizidine alkaloids. NONE. NOT THERE. And to THAT, let's add a little fact that Heather reminded me of recently and that's that water is a lousy solvent for alkaloids. So fine. We won't make COMFREY ROOT *TINCTURE*.....but the chance of ever getting enough of that dreaded alkaloid by drinking comfrey tea/infusion is simply non-existent..... It isn't there to begin with, and we're still using the wrong solvent. Anyway, that's the routine I run whenever anyone asks me. If you want, I’ll try to find that original research paper again.
LadyB

Judith Berger's very sound and grounded discussion of Comfrey in Herbal Rituals is what put all my fears to rest about this herb. She goes over all the major info from the scientific community that caused the scare, and shows how contradictory much of it is. She also talks about the herbalist Adele Dawson "who firmly stated that she attributed her good health to drinking a single cup of comfrey leaf tea each day for thirty years".
This herbal should not be out of print... it is one of the best I own and quite frankly one of the most powerful books I've ever read...
Crystal Woman