Comfrey - Symphytum officinale

Botanical: Symphytum officinale

Family: Boraginaceae

parts used: aerial parts, root
actions: anti-inflammatory, anodyne, demulcent, mucilagenous, nutritive, styptic, vulnerary

Comfrey is a perennial herb with a black, many fingered root and large, hairy broad leaves that bears small bell-shaped flowers of various colours. The flower color on our plants is a light beautiful purple.

To differentiate it from other members of the genus Symphytum, this species is known as common comfrey or true comfrey. Other English names include blackwort, bruisewort, consormol, consound, knitbone, and slippery root. Note: this is NOT Russian comfrey.

Using Comfrey in the Garden

Comfrey’s deep roots work to bring nutrients up from the subsoil. These nutrients are then made available in the abundant number of leaves it produces every year (4-5 lbs of leaves per established plant/ per year). The leaves are rich in nitrogen and potassium with a decent amount of phosphorus as well, making them a wonderful homegrown fertilizer. Researchers in British Columbia analyzed the NPK (nitrogen-phosphorus-potassium) ratio of comfrey* and discovered that the leaves have a remarkable NPK ratio of 1.80-0.50-5.30. When we compare these nutrient ratios to that of animal manure we can see how far superior comfrey is.[1] [2]

Dairy Cow: .25-.15-.25
Steer: .70-.30-.40
Horse: .70-.30-.60
Sheep: .70-.30-.90
Chicken: 1.1-.80-.50
Rabbit: 2.4-1.4-.60

Note: Naturally, nutrient values of animal or plant based manure can vary greatly from specimen to specimen.

* Air-dried powdered comfrey leaf tissues.

Comfrey grows best in soggy and marshy areas, but extremely moist conditions are not necessary to grow excellent plants. Comfrey prefers a sweet soil with a pH of 6.0-7.0 and grows best in rich, moist soil in full sun, but will tolerate some shade. It will grow well in clay or light sandy loam;in dry or wet areas. It adapts well to most any environment growing strong with deep roots. It can be propagated from its seeds during spring or by root division during autumn. The leaves and the flowering aerial parts are usually collected during the summer months. The root of comfrey is harvested during autumn.

As with most medicinal plants used today, if objective scientific research is applied, their traditional uses are substantiated or at least clarified. in Comfrey's case, due to a configuartion of events, the research that today is… Click To Tweet

Using Comfrey for Wellness

Comfrey contains an element called allantoin. Allantoin encourages cell growth and, thereby, aids in mending damaged tissue. Many of the beneficial properties of comfrey are attributed to its high content of allantoin, a substance that helps promote new skin cell growth. [3] In addition, the herb contains rosmarinic acid and additional phenolic acids that enable comfrey to function as an anti-inflammatory agent.

Comfrey Oil

When we say comfrey oil, we are talking about “infused” oil, not essential oil. Infused oil is simply herb soaked in oil for a length of time or over low heat to extract the herbs constituents into the oil.

  • For skin rashes – Comfrey oil can help in treating rashes. However, caution should be taken when it comes to deep wounds – the oil can help heal the skin so quickly that the new tissue may cover the wound before deep healing inside, resulting in an abscess or skin infection.[3]
  • As a poultice – A poultice is a good alternative if you have an infection but don’t want to apply comfrey oil directly. Here’s how to do it: blend four cups of chopped leaves and stems with one-fourth cup of carrier oil, such as jojoba, almond, or olive oil. Without straining out the herb, wrap the comfrey oil paste with a cotton cloth. Freeze this poultice to help reduce pain and inflammation. Otherwise,
    you may apply it directly on the affected area for at least 30 minutes.
  • For bone fractures – Apart from helping treat superficial wounds, comfrey oil has also been applied to fractured bones or torn ligaments in areas of the body where it is not possible to place a cast, such as a rib. It can be applied directly onto your skin or in a poultice, potentially promoting fast healing. It is also said to help reconstruct torn muscles that might have been injured.

” ‘But these are weeds, Sister. Weeds for broken bones and burns?’ The poultice was finally ready, and Gunnhilde knelt beside the boy’s head.
‘These are not weeds, Brother Cuillin, they are weapons in God’s armory.’ “
~ The Island House, by Posie Graeme-Evans

Is Comfrey Oil Safe?

Comfrey oil appears to be safe when applied to unbroken skin.

It is “discussed” as unsafe to take comfrey by mouth because of its pyrrolizidine alkaloids (PAs), which it is proposed, can cause liver damage. The US Food and Drug Administration (FDA) has recommended banning oral forms of Comfrey.

However, in the Garden Web community forum, Garden Web it was argued that the pyrrolizidine alkaloids (PAs) in comfrey are qualitatively and quantitatively less than toxic than those found in known poisonous plants, such as ragwort.
It also casts doubt that PAs cause cancer outside of laboratory experiments, and states that a toxicological study has shown that normal human use of comfrey cannot cause death or toxicity. Emphasis mine.

During studies undertaken to ascertain the elements present in comfrey, scientists have noticed that when pyrrolizidine alkaloids are present as solitary substances, they are extremely poisonous to the liver. However, the scientists are yet to ascertain whether pyrrolizidine alkaloids are also toxic when using the entire plant. In any case, they are present in tiny quantities in comfrey and sometimes they are totally lacking in samples of the dehydrated aerial parts of the plant. It has been found that the greatest intensity of pyrrolizidine alkaloids is in the roots of the plant.

Hence, until the time the scientists are able to validate or deny the safety of using the comfrey roots, it is not recommended to use the roots or herbal products enclosing them for internal use. However, it has been established that internal use of the aerial parts of the comfrey plant is harmless. Many herbalists are of the view that the legal question raised over the safety of using comfrey as a medication requires being secured by undertaking a more profound perception of the herb’s healthful aspects. I couldn’t agree more.

This may be long for an “Materia Medica” but Charles W. Kane in his book, Herbal Medicine, Trends and Traditions wrote…

As with most medicinal plants used today, if objective scientific research is applied, their traditional uses are substantiated or at least clarified. in Comfrey’s case, due to a configuartion of events, the research that today is used to site Comfrey as a toxic plant was and still is misappplied. The short story, that an array of PAs found within Comfrey are harmful agents and a number of hapatoxic cases have been linked to the plant’s usage should be looked at more closely.

  1. Not all PAs are created equal. Depending on the family – genus – species, some PA-containing plants are completely non-toxic (Echinacea) or are overt poisons (many Senecia species). These differences are due to the type of contained PA. The American garden variety falls more to the non-toxic side of the continuum, whereas Russian varieties contain higher percentages of the more toxic PA, senecionine.
  2. The few cases of hepatotoxicity that were “reported” for Comfrey use in the lated 80s/ early 90s mainly involved individuals who had pre-existing liver-centered illnesses, and/or who who were users of hapatotoxic drugs. At least one individual ingested an extraordinary amount of the herb daily (10 cups of tea/”handfuls(s) of tablets daily) – a huge dosage for anyplant.
  3. Comfrey toxicity is mainly thereoretical and is essentially based only upon animal studies. Purified PA fractions (not Comfrey) were fed to rats, who then developed hapatotoxic reactions. High administered PA to body weight ratio, and the fact that not all animals process PAs the same, factor into the alarmist result. Pigs, cows, chickens, and horses are less sensitive to PAs than rats, rabbits, goats, and sheep.
  4. Where do humans fit in? The fact is we don’t really know, but the most likely the situation with Comfrey is not as dire as some would suggest. Some perspective is needed. How many individuals die each year of liver-related pharmaceutical/over-the-counter poisonings? Hundreds, if not thousands. How many individuals have succumbed to the rational use of only Comfrey, with no pharmaceutical/prior disease history… zero!
  5. Comfrey’s overall usage history is so empty of toxicity report, it is strange that an apparent concentration of cases developed when they did. With some speculation it is not far-fetched to suggest that the few individuals supposedly affected by “Comfrey toxicity” were stricken, despite, not because of Comfrey. [4]

One last thing from Charles W. Kane’s notes…

I find it remarkable, yet typical that an individual can be on an organ transplant list, taking a slew of pharmaceuticals, drinking alchohol to excess just to dull the misery of the situation AND taking an herbal remedy. If the individual dies due to precarious health, guess who is blamed for that person’s death… you betcha… the herb. [4]

I love Charles Kane’s books.

In an old issue of Let’s Live (Oct.-Dec., 1958), H. E. Kirschner, M.D., wrote an almost unbelievable
article about several important clinical uses of Symphytum officinale.

Dr. Kirschner used comfrey in his medical practice to promote the healing of ulcers and wounds. He traces the history of comfrey back to 1568 and W. Turner’s Herball which said “of Comfrey Symphytum, the rootes are good if they be broken and dronken for them that spitte blood, and are bursten. The same, layd to, are good to glewe together freshe woundes. They are good to be layd to inflammation…” He then cites Gerard’s 1597 Herball, which indicated comfrey for ulcers of the lungs and ulcers of the kidneys, and Parkinson’s 1640 Theatrum Botanicum:

“The rootes, taken fresh, beaten small, spread upon leather, and laid upon any place troubled with the gout, doe presently give ease of the paines and applied in the same manner, giveth ease to pained joynts, and profiteth very much for running and moist ulcers, gangrenes, mortifications and the like.”

Most significant is a citation from Tournefort’s 1719 Compleat Herbal, which tells of one who “cured a certain person of a malignant ulcer, pronounced to be a cancer by the surgeons, and left by them as incurable, by applying twice a day the root of comfrey bruised, having first peeled off the external blackish bark or rind; but the cancer was not above eight or ten weeks standing.” Even allowing for a misdiagnosis, this account is interesting.

Dr. Kirschner personally observed the powerful anticancer effects of comfrey on a patient of his who was dying from advanced, externalized cancer. He prescribed fresh, crushed-leaf comfrey poultices throughout the day. He writes that, “Much to the surprise of the patient and her family,” there was obvious healing within the first two days of treatment, with continued visible improvement over the next few weeks. “What is more,” he writes, “much of the dreadful pain that usually accompanies the advanced stages of cancer disappeared,” and there was a dramatic decrease in swelling.

Dr. Kirschner concludes by regretfully saying that the cancer had already spread to the inner organs “which could not be reached with the comfrey poultices, and the woman died.”

Just in terms of quality of life, the degree of healing that did occur under the comfrey poultice treatment is of tremendous significance. Here is a “folk” remedy undeniably providing, at the very least, significant palliative relief, and to a remarkable extent reversing a cancerous growth. We can ill afford to overlook the full potential of external comfrey leaf poultices to heal sores and wounds of all types, including burns and gangrene, as well as “tumors both benign and malignant,” says Dr. Kirschner.

Taken internally as decoction (boiled root tea), Symphytum officinale is described as effective against tuberculosis, internal tumors and ulcers, and promotes the healing of bone fractures. If it is hard to understand how one simple, easy to grow and easy to apply plant can be so widely useful in healing, remember that penicillin’s supporters have made some pretty broad claims for the mold on oranges. [5]

Note: I would like to add that I would copy his entire article here for you to read, but it is copywrited. So please do yourself a favor if you would like to know more about using this herb and visit his website. (link in credits)

Video! Herbalists Rosemary Gladstar, Michael Tierra and Brigitte Mars discuss the benefits and uses of comfrey herb, also known as knit bone. Concerns about pyrrolizidine toxicity are addressed.

Susan Weed discussing true comfrey (Symphytum officinale) and concerns about pyrrolizidine alkaloids.

“If those of these times would but be, by a joint concurrence, as industrious to search into the secrets of the nature of herbs, and make trial of them. They would no doubt find the force of simples many times no less effectual, then that of compounds to which this present age is too much addicted.”
– William Cole, Adam in Eden

comfrey blooming in the evening sun


  • Rodale Guide to Composting
  • Rodale’s All-New Encyclopedia of Organic Gardening, An Illustrated Guide to Organic Gardening
  • David Hoffmann “The New Holistic Herbal”
  • Charles W. Kane, Herbal Medicine, Trends and Tradition
  • This is the writing of Andrew Saul, DOCTOR YOURSELF: Natural Healing that Works (webpage
  • MacAlister, C. J. and Titherley, A. W. (1936) Narrative of an Investigation Concerning an Ancient Medicinal Remedy and its Modern Utilities Together with an Account of the Chemical Constitution of Allantoin. London: John Bale, Sons, and Danielsson.
  • Pyrrolizidine Alkaloids in Healing Herbs, Heather Nic an Fhleisdeir August 8, 2013
  • Gerneral Information about Pyrrolizidine Alkaloids

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