Comfrey Monograph

Comfrey

(Symphytum officinale (3), S. x uplandicum (MNG))

This Materia Medica assignment (new, more in-depth style) was written by Kate Duinkerken
with additional input from Maria Noel Groves (MNG) and Liane Moccia (LM).

Common Names: Comfrey, Knitbone (3) Boneset, Boneknit, Bruisewort (4)

Family: Boraginaceae (3)

Part(s) Used: Aerial Parts, Root (3). Internal use of the leaf is generally deemed not safe, and the root is for external use only, see cautions and nuance below.

Key Actions: Demulcent, Astringent, Anti-inflammatory, Wound and Bone Healing (3), Analgesic (pain relieving), Antioxidant, Antirheumatic, Expectorant, Vulnerary (5), Emollient, and Hemostatic (4)

MNG: I don’t generally consider comfrey astringent nor drying, but herbalists never agree 100%, especially not for a plant like comfrey.

Flavor: Salty, Sweet (5), Mucilaginous Texture and Cucumber-y Aroma (MNG)

Energetics: Moist, Cooling (5) (MNG: most sources),
though some sources indicate Drying (2)

Identification/Growth:

Comfrey is a perennial, native to Europe, that grows to three feet, with thick leaves and bell-like white to pink or mauve flowers (3). It grows in all temperate regions of the world, including Western Asia, North America and Australia, thriving in moist, marshy places (3). It can be grown from seed in spring or root division in the fall (3). The smell of the leaf is fresh, slightly salty, cucumber-like and mildly sweet, indicating the mineral and polysaccharide content (5). Breaking open a leaf (MNG: or root) will reveal a slimy mucilage (5).

MNG: Russian comfrey is often grown in gardens as “comfrey” and used somewhat interchangeably. It’s reported to be a hybrid of S. officinale and S. asperum originating in Russia, eventually sent to London and then the United States a a popular forage and garden crop (note cautions).

Harvesting/Preparation/Dose:

The root is harvested in the fall when the allantoin levels are highest (3). Leaves and flowering tops are harvest in the summer (3). MNG: Note leaves have fewer of the potentially problematic PAs – discussed in cautions – and older leaves generally have fewer PAs than younger leaves… though may still be problematic as PA counts vary widely batch to batch.

TOPICAL PREPARATIONS

Topical preparation – prepare leaf oil using the alcohol intermediary oil method, or infuse the leaves or root using the double boiler method. Apply comfrey topically as a apoutice, fomentations, cream, salve, ointment, balm, paste, wash, bath, sitz bath, mouthwash, vaginal irrigation, or enema (4).
Infused oil of leaves – apply to sprains (3).
Chopped leaves – apply as a poultice to boils (3).
Ointment of leaves – apply to bruises (3). 5-30% root extract, applied 3 times a day (5).
Topical Tincture – fresh roots 1:2 @70-95%alcohol; second cutting of fresh leaves 1:2 @70-95% alcohol, dry leaves 1:5 @60% alcohol, consume 5-60 drops, up to three times daily (4). Apply root tincture undiluted to acne (3).

HIGHLY DILUTE REMEDIES – SAFE FOR INTERNAL USE

Homeopathic Symphytum tablets – administered to stimulate bone mending (4).
Flower essence – used for energetic grounding and structure (4).

INTERNAL/ CONTROVERSIAL & SAFETY CONCERNS – SEE CAUTIONS

Tea – prepare and infusion of the leaf or decoction of the root; consume 4-8oz up to 3 times a day (4)
Honey – fresh root honey @1:4 – consume 1tsp up to three times daily. (Source?)

Medicinal Uses:

Traditionally used in healing broken bones, Comfrey is considered a wound-healing herb (3). Comfrey contains up to 4.7% Allantoin, which is a cell-proliferant that stimulates the repair of damaged tissues (3). It is considered an anti-inflammatory because of the rosmarinic and phenolic acids (3). It contains about 29% mucilage (3). Despite being mucilaginous and moistening, comfrey is also considered to be drying (MNG: by some herbalists) because it prevents fluid loss, or bleeding and stops the weeping from wounds (2).

In Germany and other place in Europe, Comfrey is widely used for sprains, bruises, and sports injuries (3). Studies indicate Comfrey has a “very good” effectiveness rate and completed healing three days faster than those using a placebo (3). Other studies show Comfrey helps when used as an anti-inflammatory in sprained ankles, osteoarthritis, and lower back pain (3). Comfrey’s ability to promote the healing of bruises, sprains, fractures and broken bones has been known for thousands of years (3). It encourages ligaments and bones to “knit” together firmly (3). A comfrey compress applied immediately to a sprained ankle can significantly reduce the severity of the injury (3). The combination of tannins and mucilage helps to soothe bruises and scrapes (3).

Comfrey preparations can be applied to heal problems such as insect bites, scars, skin inflammation, acne and mastitis (3).

The leaves (MNG: and roots) are moist and mucilaginous, due to the polysaccharides (5). The cooling and soothing properties stem from the anti-inflammatory properties (5). When the mucus from the plant dries, the skin feels tacky and tight, due to the high tannin content, which is astringent and toning for surfaces and mucous membranes (5).

Comfrey contains some constituents, such as allantoin, which move rapidly through tissues, speeds up wound healing, and reduces the production of scar tissue (5).

Clinical studies show the efficacy of Comfrey as a topical application for swelling of the muscles and joints in degenerative arthritis, acute myalgia, sprains, contusions and strains after sports injuries and accidents (5).

Comfrey root has expectorant and mild astringent properties, where a gargle and tea could ease sore throat, laryngitis, pharyngitis, tonsillitis, hoarseness, and as a mouthwash for bleeding gums (4). As a soothing demulcent, a Comfrey root decoction used short-term reduces inflammation, stimulates healing in mucous membranes and reduces intestinal permeability (4). It eases digestive conditions such as acid indigestion, gastroesophageal reflux disease (GERD), gastric and duodenal ulcers, diarrhea, and constipation (4). Comfrey tea can be consumed following an intestinal infection or during flare-ups of Crohn’s disease, ulcerative colitis, or IBS (4). MNG: However, due to rising concerns of comfrey’s PA content and potential liver toxicity when consumed – discussed in cautions – internal use is technically illegal in the United States and many herbalists opt to use safer alternanatives like marshmallow, slippery elm, gotu kola, plantain, or calendula.

Other Uses

Energetically, Comfrey relates to the base chakra, where energy is stored (5).

Comfrey flower essence is for those who lack structure and form in their lives, who need to develop a solid base, to give a sense of order where chaos is felt (5).

Comfrey is a powerful healer of raw and sensitive emotional wounds and trauma, providing a soothing and grounding protective layer while the person heals (5). Comfrey also bring in determination, cohesiveness and the ability to fuse back together what has come apart, while encouraging growth and change (5).

Kate’s Personal Experience:

I make a comfrey salve with sesame oil and dried comfrey leaves. I have not used the root that I remember. We use the comfrey salve for “special” occasions, lol, like deep bruising or bad cuts that also result in bruising around the area of the cut. We try and use it minimally in fear of liver toxicity, which I was taught about somewhere else. Now that I understand more about comfrey, I don’t think we should fear it as much as I had been. I feel like as long as your wound is super clean then you have less of a chance of sealing in a bacterial-causing infection. It also seems like Europeans are using it regularly and don’t have liver issues from it. My kids do a lot of sports, construction and things that result in injury. I think we can use more comfrey than we did before, 10 days maximum.

(LM: I really believe that external use is safe, even for prolonged use. I would use caution, or avoid, internal use.)

Christa Sinadinos mentions in her book that in Ireland, comfrey was consumed to improve circulation and nourish the blood (pg 148). This triggered a memory for me that my paternal grandmother, who lived in Ireland until a teen, used Comfrey a lot for my grandfather, also for Ireland, who struggled with circulation complications due to type I diabetes in the 1980’s. I remember him putting the ends of his fingers, which eventually lost all blood flow, in Comfrey “soup” on the table and they would have us girls put our hands in something liquid for our hands as well so we wouldn’t feel left out.

IMPORTANT: Cautions

Safety concerns grew in the early 1990’s, (MNG: as human case reports of liver failure and death occurred) and more long-term studies on Comfrey resulted in liver toxicity and liver tumors, resulting in a blanket ruling by the FDA discouraging the internal use of the herb (4). After reading Christa Sinadinos presentation on Comfrey, it appears she feels that there is some wiggle room in its usage internally, depending on the species, preparation and part used (4). MNG: However studies also show that the PA content can vary widely from batch to batch, making it a bit like “Russian roulette”. Claims of different species containing more/less PAs are not well substantiated when you review a broader set of literature and batch tests – see the Comfrey Central resource further below for a chart.

LM: I think many herbalists agree SHORT TERM internal use is likely safe for things like GERD and stomach ulcers.

MNG: But many herbalists prefer to be cautious and opt for safer and less controversial/illegal herbs for internal healing benefits such as marshmallow, slippery elm, plantain, gotu kola.

Not for internal use (3). Not to be used by children (4). Restricted in some countries (MNG: inluding USA; illegal to sell for internal use) (3). Do not use during breastfeeding or pregnancy (3). Due to potentially toxic constituents called pyrrolizidine alkaloids (PAs), Comfrey should only be used externally, for a duration of no more than ten days (LM: I think the 10 day limit is old/unsubstantiated)(5). Comfrey should not be taken t the same time as herbs or medications which induce CYP3A liver enzymes, including St. John’s wort, schisandra and epilepsy medications (5). Due to the risk of additive toxicity, comfrey should not be taken alongside other PA-containing herbs or supplements, including boneset, borage, butterbur, coltsfoot, gravel root, hemp agrimony and tansy (5).

Do not use on dirty wounds as rapid healing can trap dirt or pus (3).

Maria’s Perspecive and Additions on Comfrey and PA Safety:

I love comfrey, but there are real safety concerns: Let me preface this by saying I love comfrey as a plant and medicine and feel deeply connected to it, but I am also moderately cautious in how I work with it. While many herbalists including some I deeply respect consider comfrey much maligned and generally safe, my own exploration into the literature and care reports gives me pause. I believe much of the herbal community is repeating outdated, inaccurate, and unsafe rhetoric. Comfrey concerns are real and relevant, not just from lab studies of isolated constituents force-fed to rodents in high doses.
There is a rare but very real and potentially dire risk of liver damage from comfrey.
- Human Cases Exist: There are human case reports from both large and more typical doses of regular comfrey (including leaf-only and water-extract only) and other PA-containing plants causing liver failure and, in many cases, death. One case was shared on an herbal forum by an herbalist I know whose mother consumed the typical “super infusion” style comfrey leaf tea regularly and died of PA-induced liver failure. Other cases in the literature include a man with cancer eating copious amounts of comfrey doing a “cleanse.” Another is a woman consuming a mixed herbal formula for respiratory health that contained the PA-plant coltsfoot; she was fine, but she was pregnant and her baby was born with veno-occlusive disease and died. (Some of these and additional cases are outlined via the Comfrey Central and Paul Bergner resources below.)
- PA Content and Impacts Vary Widely and Somewhat Unpredictably: Studies and cases also clearly show that PA content varies widely batch to batch and that people also have individual and sometimes unpredictable responses to PAs. It’s true that generally the roots have far higher PAs than the leaves, and that older leaves (our “safest” option) have fewer PAs than younger leaves. Some herbalists report that one species is safe while another is not. This isn’t really true (see the Comfrey Central charts). What is true is that PA content varies widely batch to batch. So, one herbalist’s patch of one species may be low while another species in their garden, but when you look at multiple batch tests, you’ll see that both species can be very low or extremely high. Additional nuance: Repeated/later harvests may have fewer PAs vs earlier harvests. Richer soil, sunnier spots, and drier soil tend to produce higher PA plants vs poorer soil, shady, and more moist spots.
- Solvency? I haven’t seen much supportive data, but the belief is that alcohol extracts PAs more readily while water and especially oil, less. That said, case reports of liver toxcity in humans have occurred from eating comfrey as food, drinking comfrey as tea, and low doses of coltsfoot in an encapsulated formula.
- It’s all a game of chance. How willing are you to risk your liver (or your clients’, family’s, livestocks’) for healing properties you can probably get from other plants much more safely??
- How Comfrey/PA Liver Damage Presents: The type of damage comfrey and other pyrolizadine alkaloid(PA)-rich plants cause is unique, slow, cumulative and doesn’t show symptoms nor lab abnormalities until it reaches an advanced, life-threatening state. PA-induced liver damage specifically causes veno-occlusive disease, which has a different presentation than other causes of liver damage (Tylenol/acetametophin, alcohol, medications, diabetes-induced fatty liver disease, etc).
Topical Safety and Considerations:
- While studies suggest that PAs can be absorbed via the skin, this seems to be minimal, and I am of the mindset that topical use is likely safe. Many studies show benefits for a wide range of ahces/pains, repair (as Kate notes), and I love working with comfrey leaf oil clinically in my practice for this. I probably wouldn’t, say, bathe a baby in comfrey tea regularly, though.
- However, because comfrey heals tissue so rapidly, it can seal in infection, and I have also seen it cause fast but low quality wound remodeling – thick keloid ropy scars, etc. I generally prefer slightly slower but more sophisticated woung healing herbs like comfrey, gotu kola, plantain, and St. John’s wort (among many others). Though I would consider comfrey topically in a lower percent in formula, topically on properly set bones, and for general resolution repair/integrity of old wounds.
Other Popular Comfrey Uses
- Animal Fodder? Even though many people use comfrey as fodder for livestock – it is indeed nutritious (rich in minerals and protein) – it still has the potential to cause liver failure in animals, just like it does in humans.
- Garden Ammendment? Unfortunately, new studies on PA-rich plants like senecio show that nearby plants like lemon balm, parsley, and chamomile can update PAs in somewhat similar levels as the PA-containing plant, which is very concerning. This calls into question the practice of using comfrey as a fertilizer crop or fermented tea. (Which I myself reocmmended in my early books before this research emerged. I looked over the full text studies hoping to find a loophole, but the results while preliminary were very concerning. I now keep my comfrey separate from crops I ingest.)
- Homeopathic? Flower Essences? In addition to most topical situations. I am also comfortable with comfrey internally via highly dilute remedy formats: flower essence and 30C/10X or higher dilution homeoapathics (NOT 1X, which is still 10% comfrey). In these high dilutions, there is basically no chemical representation of PAs nor the plant itself.
Note that other PA containing plants include senecio (very toxic and not as popular in herbal medicine), borage (lower amounts of PAs), coltsfoot, and boneset/Eupatorium.
Side Note On Poisonous Look-Similar Leaves: Before it blooms, comfrey leaves are not particularly distinctive and sometimes mistaken for other plants, such as the incredibly toxic plant foxglove. Just one cup of tea or leaf in your smoothie of foxglove is rapidly deadly (where as the risk of a single dose of comfrey is quite low). This is totally separate from the PA-liver toxicity discussion (totally different speed, mechanism of death, etc) but important to note to proper ID is important. A few case reports of death from foxglove (when people thought they were harvesting comfrey) exist.

Sources & Resources

Kate’s Sources:

Note that there are at least three different sources/perspectives including at least one science/evidence-based source (and a majority herbalist-based), as per assignment minimum requirements.

Photo Credit (in her original HW, but not posted here on this blog): Muskogee Phoenix. All the Dirt on Gardening: Comfrey. All the Dirt on Gardening: Comfrey is a power plant | Lifestyles | muskogeephoenix.com. Accessed August 13, 2025. Extra Source.
Wood, Matthew. The Practice of Traditional Western Herbalism: Basic Doctrine, Energetics, and Classification. Herbalist/Experience Based.
Chevallier, Andrew. Encyclopedia of Herbal Medicine: 560 Herbs and Remedies for Common Ailments. 2023. Herbalist/Experience Based.
Sinadinos, Christa. The Essential Guide to Western Botanical Medicine. Herbalist/Experience Based.
Herb Reality. Comfrey | Herbs | Herbal Reality. Accessed August 14, 2025. Science/Evidence Based.

Additional resources from Maria

This goes beyond what I would expect from a beginner/intermediate student in their homework, but I feel like many would find these more advanced sources insightful:

On Comfrey & PA Safety

Comfrey Central, by Dorena Rode, last updated 2004, is loaded with helpful, evidence-based, and minimally biased information on comfrey and PAs, supported in part by the National Institutes of Health (NIH) National Center for Complementary and Alternative Medicine (NCCAM) fellowship (#F31 AT00656-01). For more information about funding for complementary and alternative medicine research visit the NIH NCCAM web site. (This statement doesn’t imply that the material in this site was reviewed, approved or authorized by NCCAM.) https://www.comfreycentral.com/ including…
- Case reports through 1992 (and other study data)
  - Note that Maria Noel Groves is aware of at least one other human case – an herbalist in the USA community on a forum reported that her mother followed the popular super-infusion style leaf tea, drinking regularly, and died of veno-occlusive disease-associated liver failure; however, this case anecdote may not be available in the scientific journeys.
- PAs in comfrey including charts of data on different parts and species – you will see that the quanties vary WIDELY plant to plant and that none of the common species can be assumed to be low/free of PAs, though leaves generally do have far fewer PAs than roots (they can still provid potentially toxic levels) https://www.comfreycentral.com/research/comfrey_pa.htm
Additional articles and studies: de la Foret, Easley, Dharmananda, Comfrey studies on PubMed, PAs on PubMed. Herbalist Paul Bergner also speaks widely on this, such as in this MedHerb article.
Studies on PA-containing plant transfer via soil to other plants (note that the full text for these is harder to get, sometimes you can find them via Sci-Hub, but the links change often) Nowak and Selmar , these studies were more specifically on Senecio (a more toxic plant) but likely also occur with comfrey. While one study by Chmit (full text here) determined a lesser risk, the evidence they provided is less convincing – and odd that they list “comfrey” on the study title yet use a completely different and obscure plant (Lappula squarrosa) in the resarch trials. More nuanced research would be great to help clarify all of this further, ideally on the comfrey species we love and grow.

Russian Comfrey

Botanical Society of Scotland, Russian Comfrey May 26, 2025 https://botsoc.scot/2025/05/25/plant-of-the-week-may-26th-2025-russian-comfrey-symphytum-x-uplandicum/
Strictly Medicinal Seeds, Richo Cech, profiles on Russian Comfrey and True Comfrey

Sample Monograph by student Kate Duinkerken with additions from Maria Noel Groves, RH(AHG) and education advisor Liane Moccia, RH(AHG). Featuring the newer, more detailed monograph homework style.

About Kate Duinkerken

Passionate about learning, Kate has spent many years becoming knowledgeable in the healing arts, with certifications as a Transformational Healing Practitioner, Child Meditation Facilitator, Usui Reiki Master, and completing a Shaman Apprenticeship with Bloom Post. Kate has also completed many other courses in religious studies and practices, hand and foot reflexology, and mindfulness practices, learning comprehensive and empowering ways of helping others release stagnant energies from their bodies. Working as an intuitive energy healer for the past eighteen years, Kate started learning herbalism under the guidance of Maria Noel Groves with Wintergreen Botanicals. Ultimately, Kate desires to learn how to integrate herbs to help facilitate the healing of the physical body, while complementing the release of stagnant energy from the body and surrounding systems. It is with great honor that Kate serves those in her community, and herbalism is a perfect tool to offer to those on their healing journey. Kate’s favorite herbal therapies include making broths, formulating teas, providing oil formulations, and making salves for her family, friends, and others who have been called to receive these remedies. When Kate is not spending time with her family or working in the community, she enjoys spending time with the animals on her hobby farm, hiking, or working in the garden.

Kate has completed Wintergreen Botanicals’ Home Herbalist and Beyond the Home Herbalist series and joined the team as an education advisor in 2025-2026.

Comfrey Photographs by Maria Noel Groves (the species pictured is likely S. x uplandicum)

The statements made on this blog have not been evaluated by the FDA and are not intended to diagnose, prescribe, recommend, treat, cure, or offer medical advice. Please see your health care practitioner for help regarding choices and to avoid herb-drug interactions.

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