Comfrey is sometimes called boneset, bruisewort, comfrey leaf, comfrey root, knitbone, or its scientific name Symphytum officinale and belongs to the Boraginaceae (Borage) family. It is native to Britain and extends throughout most of Europe into Central Asia and Western Siberia. Comfrey has been used for over 2,000 years to help broken bones, sprains and rheumatism, liver problems, gastritis, ulcers, skin problems, joint pain, contusions, wounds, gout, hematomas, and thrombophlebitis (1,2).

Comfrey can be identified by its large, oval, hairy leaves and drooping flower clusters. The plant thrives in moist, marshy (waterlogged) environments, grows slightly over 3 feet tall, and feels stiff due to its hairy leaves (3). Depending on the species, the flowers are small, bell-shaped, and either cream or pink, purple or mauve. A cream color indicates common comfrey, while purple is Russian comfrey. However, the two can cross-pollinate, resulting in multi-color flowers. Meanwhile, when you pull comfrey for the roots, they’re black (4).

Comfrey can be grown from seed in the spring or root in the fall. The roots are also pulled in the fall, while the leaves and flowers are harvested in the summer. If you plan to forage for comfrey, always harvest ethically. Never collect anything from private property without direct permission. When harvesting from public spaces, consider the impacts on native plant populations. Due to the uncertainty of surrounding plants, be careful not to disturb them as they could be an endangered or threatened species. Always be kind to the earth and only harvest what you need.

According to one of my favorite herbal resources, the Encyclopedia of Herbal Medicine, comfrey’s key constituents are allantoin, mucilage, triterpenoids, phenolic acids (rosemarinic acid), asparagine, pyrrolizidine alkaloids, and tannins. Some of its herbal actions include:

• Anti-inflammatory: helps the body control inflammation.
• Astringent: constricts mucus to reduce discharge and lessens bleeding from minor wounds.
• Demulcent: coats, soothes, and protects irritated or inflamed tissue.
• Fracture-healing: heals broken bones and supports callus formation.
• Vulnerary: heals wounds by replacing damaged or destroyed tissue with new tissue.

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Research-Backed Health Benefits of Comfrey

Some people consider this perennial (meaning it lives more than two years and regrows each spring) a weed; however, its medicinal properties are highly recognized in herbalism. Comfrey is most commonly known for its pyrrolizidine alkaloids (PAs) content, which is considered toxic when ingested. Some amazing health benefits of comfrey include the following:

Antimicrobial Properties

An antimicrobial property is when a substance, or in this case, an herb, can kill or suppress the spread of microorganisms such as bacteria, viruses, protozoans, and fungi (5). Comfrey’s antimicrobial properties largely come from its alkaloid compounds (6). One study demonstrated comfrey extract’s potential antimicrobial effects on several bacterial strains tested, especially against Staphylococcus aureus (7). Another study noted that comfrey had antibacterial properties against both gram-positive and gram-negative bacterial strains except chloroform solvents at higher concentrations between 75% and 100% (8). However, a final study found comfrey root extract demonstrated low antibacterial potency against E. coli and Salmonella Typhimurium (9).

Antifungal Properties

An antifungal property is when a substance, or in this case, an herb, can fight the growth of fungi pathogens that could harm your health, such as ringworm, athlete’s foot, tinea versicolor, toenail fungus, and jock itch (10). Although there haven’t been many studies, even mainstream sources acknowledge that comfrey may possess antifungal properties (11). One study indicated comfrey leaves strongly inhibit fungi, such as the germination of Erysiphe graminis conidia and uredospores of Puccinia graminis (12). Another study found isolated alkaloids from Symphytum sylvaticum (common comfrey) root effective against several fungal cultures (13).

Anti-Inflammatory Properties

Although inflammation is a natural bodily response, chronic inflammation can lead to detrimental health effects. Chronic inflammation has been linked with many diseases, such as type 2 diabetes, asthma, and certain cancers (14). Comfrey is widely known for its anti-inflammatory properties. One study noted comfrey root’s strong historical record in treating blunt injuries due to its anti-inflammatory, de-swelling, and pain-relieving properties (15). Another study stated comfrey was “clearly superior” regarding pain reduction and ankle edema compared to placebo in the treatment of ankle (distortions) sprains (16). One study found comfrey extract’s anti-inflammatory properties equal to or greater than diclofenac, a nonsteroidal anti-inflammatory drug (NSAID) (17,18).

Pain-Relieving Properties

As of 2016, an estimated 20.4% of U.S. adults (50.0 million) had chronic pain, and 8.0% of U.S. adults (19.6 million) had high-impact chronic pain (19). Clinical studies have found the topical application of comfrey beneficial for many forms of pain (20). One study noted pain relief for muscle and joint pain (21). Another study found a combination of comfrey root and methyl nicotinate (a methyl ester of niacin) demonstrated superiority in easing upper and lower back pain compared to other treatments (22). Other studies have seen consistently promising results for osteoarthritis pain when using topical comfrey without any adverse events (23,24).

Wound-Healing Properties

Due to comfrey’s antibacterial, antifungal, and anti-inflammatory properties, comfrey can provide exceptional wound-healing properties. Wound healing is the complex and dynamic process of restoring damaged tissue structure as closely as possible to its normal state (25). One study showed that comfrey could help heal abrasion wounds (26). An in-vitro (test tube) study found that when comfrey was added to three pharmaceutical formulations at 8% concentration, it supported the repair of damaged tissue by induced collagen deposition (27). Another study demonstrated that the topical application of comfrey cream led to a quicker regeneration of skin cells within 4–7 days (28). A final study explains comfrey’s allantoin compounds induce a wound-healing mechanism by regulating inflammatory responses and stimulating important tissue-forming functions like fibroblastic proliferation and extracellular matrix synthesis (29).

Fracture-Healing Properties

Fracture healing is a form of wound repair influenced by the recruitment of cells and the expression of genes to repair a broken bone (30). When a bone is healing, it follows three phases: inflammation, reparative, and remodeling, which lead to the formation of a callus, signifying it has healed (31). Research has found that comfrey stimulates granulation and tissue regeneration while supporting callus formation (32). In an animal study, comfrey promoted increased radiographic bone density around titanium implants when administered during the initial bone-healing period (33). Even mainstream sources acknowledge the use of comfrey on sprains and broken bones (34).

Anticancer Properties

In 2021, there were 1,777,566 new cases of invasive cancer in the United States, with almost 10 million people who lost their battle with cancer worldwide (35,36). In other words, one out of every six deaths was cancer-related. That is a lot; however, a diagnosis or genetic predisposition doesn’t define your end result. Genetics may load the gun, but environmental factors and lifestyle choices ultimately pull the trigger. Thankfully, comfrey may help. One study found that poly[3-(3, 4-dihydroxyphenyl)glyceric acid] (p-DGA) from caucasian species of comfrey is more effective compared to its synthetic derivative, syn -2, 3-dihydroxy-3-(3, 4-dihydroxyphenyl) propionic acid (m-DGA) against some prostate cancer cells (37).

Safety Information, Contraindications & Interactions

The mainstream states comfrey is possibly safe when used on unbroken skin in small amounts for less than six weeks. They claim the poisonous chemicals in comfrey can pass through the skin, so it is possibly unsafe to use comfrey on broken skin or to apply large amounts for more than six weeks. They go on to say it’s likely unsafe when taken by mouth or applied to the skin while pregnant or breastfeeding. Supposedly, the pyrrolizidine alkaloids (PAs) in comfrey are absorbed through the skin and might cause congenital disabilities, so they urge to avoid use during pregnancy and breastfeeding (38).

According to trusted herbalist Richard Whelan, external applications of comfrey leaf and root have no problem regarding potential toxicity and work beautifully. He states he uses a great deal of comfrey leaf and root in compresses and creams for a person with wounds or sores that are not healing well.

Richard Whelan states the internal use of comfrey has to be undertaken with great sensitivity and care, or not at all. He notes that comfrey has real potential to harm the liver and has recently performed fewer miracles in his practice. He says that in the rare instances he works with it, he takes extra precautions to look for characteristic hallmarks of liver stress in the patient by doing frequent blood tests. Richard urges anyone not trained in herbal medicine or who has undergone rigorous study into the scientific literature of comfrey to refrain from internal self-medicating with this plant.

Mr. Whelan explains his thoughts on when internal use is justified, are well-represented here by the great English herbalist Thomas Bartram. He writes:

“It would appear that the use of the root of Symphytum officinale may be justified in the treatment of severe bone diseases for which it has achieved a measure of success in the past, such as rickets, Paget’s disease, fractured bones etc. its benefits outweighing risks. Few other medicinal plants replenish wasted bone cells with the speed of Comfrey.”

Richard Whelan says comfrey combines extremely well with calendula and plantain weed to help heal. He adds it would be much wiser for many people to use either of those great herbs for any internal wounds and only add comfrey if the treatment is being used externally. Comfrey can also work particularly well with a little licorice or marshmallow root for cracks, cuts, and dry skin problems that are not healing well (39).

Although Richard did not mention the safety of topical comfrey while pregnant or breastfeeding, several herbal resources consider it unsafe; however, I found no evidence or relevant published information on the negative effects of comfrey in these groups (40). Actually, the only concern was getting comfrey on the baby, which could result in an accidental ingestion (41). One scientific article notes:

“Comfrey, also a traditional vulnerary, is generally considered safe for topical use in small amounts and for short durations on open skin. However, because of the potential for hepatotoxicity from pyrrolizidine alkaloids via ingestion by babies from the mother applying it to the nipples, this herb is NOT considered optimal for topical use on the nipples of breastfeeding mothers other than acutely. Residues should be thoroughly wiped off prior to nursing, and use should be limited to several days (42).”

With that said, I would be comfortable using comfrey topically while pregnant or breastfeeding.

However, comfrey ingestion is restricted in many countries. Although a scientific paper claims that comfrey might not be as dangerous to humans as current restrictions indicate, research says something else. One study stated that comfrey can result in hepatotoxicity (liver toxicity) in livestock and humans and carcinogenicity in experimental animals. They go on to assume this is a result of the plant’s pyrrolizidine alkaloids (PA), stating:

“The mechanisms underlying comfrey-induced genotoxicity and carcinogenicity are still not fully understood. The available evidence suggests that the active metabolites of PA in comfrey interact with DNA in liver endothelial cells and hepatocytes, resulting in DNA damage, mutation induction, and cancer development. Further, the two agents share common mechanisms of drug metabolism and carcinogenesis. Overall, comfrey is mutagenic in liver, and PA contained in comfrey appear to be responsible for comfrey-induced toxicity and tumor induction (43).”

That said, when it comes to comfrey consumption, out of caution, I prefer to use one of the other two to three thousand less-risky medicinal herbs out there.

How to Use Comfrey & Product Recommendations

When I make homemade herbal remedies, I try to buy herbs locally. When buying locally isn’t an option, I typically purchase from one of the following brands I trust:

• Anthony’s Goods
• Frontier Co-op
• Starwest Botanicals

Looking for additional herbal suppliers? Check out my post, 3 Ways to Source Herbs.

I have yet to have the opportunity to make herbal remedies with comfrey, although I’ve been thinking about a homemade calendula salve with comfrey in it. Aside from that, to my understanding, the best preparation methods when working with comfrey include the following:

• Herbal poultices from the leaves
• Herbal salves from the leaves – learn how to make an herbal salve
• Herbal tinctures from the root – learn how to make an herbal tincture
• Topical oil infusions from the leaves (only apply to unbroken skin) – learn how to make a topical oil infusion

If making your home remedies isn’t quite your thing, I recommend a few premade herbal products, including:

• Dr. Christopher’s Comfrey Ointment is a basic herbal salve made from organic comfrey leaf in a beeswax base and extra virgin olive oil. It has no added fillers or chemicals. It is for external use only.
• Herb Pharm’s Original Salve is a multi-purpose herbal salve for minor cuts, abrasions, and burns. This salve is for external use only and contains comfrey root, St. John’s wort, calendula, mullein, and other herbs in a soothing base of organic olive oil, bee’s wax, and propolis.

Product Disclaimer

Product recommendations are affiliate links. I do not own or make these products. Recommendations are selected according to ingredients at the time article was written and can change at any time. I encourage you to double-check ingredients and research each company to ensure they’re suitable for your journey.

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