Omnia SanaCommon names in 30 European languages →
The complete database record: 4 documented constituents, 4 pharmacological actions, 10 traditional / indicated uses, with 18 cited sources.
Botanical Description
Robust, hairy perennial herb (Boraginaceae), 60-120 cm tall, with a thick, black-skinned, mucilaginous taproot. Leaves are large, broad, lance-shaped and bristly-hairy, running down the stem as raised wings (decurrent) - the leaf base's smooth, untoothed margin is a key feature distinguishing it from toxic foxglove. Drooping clusters of tubular, bell-shaped flowers are cream, pink or purple depending on variety.[11]
Habitat & Distribution
Native to Europe and western Asia, growing in damp ground - riverbanks, ditches, damp meadows and waste ground - and widely cultivated.[11]
Harvesting
Leaves are cut during the growing season (before flowering is often preferred for lower pyrrolizidine-alkaloid content); root is dug in autumn or spring from mature plants.[11]
Key Constituents
The key cell-proliferative constituent underlying comfrey's wound-healing reputation.
Contribute to the soothing, demulcent texture of the leaf and root.
Contribute to antioxidant and anti-inflammatory activity.
Hepatotoxic constituents naturally present in the whole plant; the reason internal use is not recommended and processed/detoxified extracts are used for research.
Pharmacological Actions
Traditional & Indicated Uses
inferred from anti-inflammatory action
inferred from analgesic action
inferred from vulnerary action
inferred from analgesic action
inferred from anti-inflammatory action
inferred from anti-inflammatory action
more plants for swelling / fluid retention →detailed sources →
inferred from anti-oedematous action
inferred from vulnerary action
Traditional Use & History
Comfrey has one of the strongest traditional reputations of any European herb for wound healing and bone/tissue repair - the folk names 'knitbone' and 'boneset' reflect this - owing to its high allantoin content, which stimulates cell proliferation. Because the plant also contains hepatotoxic pyrrolizidine alkaloids, modern regulatory use is restricted to topical preparations only, for minor bruises and sprains, and internal use (teas, tinctures) is no longer recommended.[11]
Preparations
The officially recognised European herbal-monograph preparation, for minor bruises and sprains, short-term use only.
Dosage
EU herbal-monograph guidance describes comfrey root preparations applied topically for minor bruises and sprains in adults, for a limited duration (commonly up to about 10 days); do not apply to broken skin or near eyes/mucous membranes. Comfrey must never be taken internally (no teas, tinctures or capsules) because of its pyrrolizidine alkaloid content. Educational reference only, not a prescription.
Safety, Cautions & Contraindications
Big headline: Comfrey naturally contains pyrrolizidine alkaloids (PAs), which can seriously harm the liver if taken internally (Staiger, 2012; EMA, 2015). • Do not ingest comfrey (no teas, no internal tinctures, no capsules), because PA exposure from internal use is the main safety problem (Staiger, 2012; Bach et al., 1990). • Topical use only, short-term: EU herbal guidance describes comfrey root preparations for minor bruises and sprains in adults, and recommends limited duration (commonly up to about 10 days) (EMA, 2015; EMA/HMPC, 2024). • Do not apply to broken skin (open wounds, damaged/irritated skin) and avoid eyes/mucous membranes (EMA/HMPC, 2024). • Pregnancy & breastfeeding: best avoided (not enough safety margin for medicinal use) (EMA/HMPC, 2024). • Children/adolescents: not recommended for medicinal topical use in EU monograph context (EMA/HMPC, 2024). • If you have liver disease or take medicines that stress the liver, skip comfrey completely (risk management logic based on PA concern) (Staiger, 2012; EMA, 2015). • Skin reactions: mild rash/irritation can occur; stop if it irritates (Smith and Jacobson, 2011).
Duke (2002) classifies common comfrey (Symphytum officinale) with anti-inflammatory and wound-healing properties, supported by allantoin content (promotes cell proliferation). However, comfrey also contains hepatotoxic pyrrolizidine alkaloids. Internal use is no longer recommended, and Commission E approved only external use. Duke emphasizes that pyrrolizidine alkaloids are cumulative hepatotoxins associated with veno-occlusive disease, and prolonged or internal use is contraindicated (Duke, 2002).
Dangerous Lookalikes
Harvest Readiness
[12]
[12]
External Identifiers
References & Sources
- Syarifah, A.N., Suryadi, H., Hayun, H., Simamora, A. and others (2023) 'Detoxification of comfrey (Symphytum officinale L.) extract using natural deep eutectic solvent (NADES) and evaluation of its anti-inflammatory, antioxidant, and hepatoprotective properties', Frontiers in Pharmacology, 14, pp. 1012716. doi:10.3389/fphar.2023.1012716 Preclinical
https://doi.org/10.3389/fphar.2023.1012716 - Melnyk, N., Popowski, D., Strawa, J.W., Przygodzinska, K. and others (2023) 'Skin microbiota metabolism of natural products from comfrey root (Symphytum officinale L.)', Journal of Ethnopharmacology, 318(Pt B), pp. 116968. doi:10.1016/j.jep.2023.116968 Preclinical
https://doi.org/10.1016/j.jep.2023.116968 - Trifan, A., Skalicka-Wozniak, K., Granica, S., Czerwinska, M.E. and others (2020) 'Symphytum officinale L.: Liquid-liquid chromatography isolation of caffeic acid oligomers and evaluation of their influence on pro-inflammatory cytokine release in LPS-stimulated neutrophils', Journal of Ethnopharmacology, 262, pp. 113169. doi:10.1016/j.jep.2020.113169 Preclinical
https://doi.org/10.1016/j.jep.2020.113169 - Brown, A.W., Stegelmeier, B.L., Colegate, S.M., Gardner, D.R. and others (2016) 'The comparative toxicity of a reduced, crude comfrey (Symphytum officinale) alkaloid extract and the pure, comfrey-derived pyrrolizidine alkaloids, lycopsamine and intermedine in chicks (Gallus gallus domesticus)', Journal of Applied Toxicology, 36(5), pp. 716-725. doi:10.1002/jat.3205 Preclinical
https://doi.org/10.1002/jat.3205 - Trifan, A., Wolfram, E., Esslinger, N., Grubelnik, A. and others (2021) 'Globoidnan A, rabdosiin and globoidnan B as new phenolic markers in European-sourced comfrey (Symphytum officinale L.) root samples', Phytochemical Analysis, 32(4), pp. 482-494. doi:10.1002/pca.2996 Preclinical
https://doi.org/10.1002/pca.2996 - Nastic, N., Borras-Linares, I., Lozano-Sanchez, J., Svarc-Gajic, J. and others (2020) 'Comparative Assessment of Phytochemical Profiles of Comfrey (Symphytum officinale L.) Root Extracts Obtained by Different Extraction Techniques', Molecules, 25(4), pp. 837. doi:10.3390/molecules25040837 Preclinical
https://doi.org/10.3390/molecules25040837 - Frost, R., MacPherson, H. and O'Meara, S (2013) 'A critical scoping review of external uses of comfrey (Symphytum spp.)', Complementary Therapies in Medicine, 21(6), pp. 724-745. doi:10.1016/j.ctim.2013.09.009 Meta-analysis / review
https://doi.org/10.1016/j.ctim.2013.09.009 - Trifan, A., Opitz, S.E.W., Josuran, R., Grubelnik, A. and others (2018) 'Is comfrey root more than toxic pyrrolizidine alkaloids? Salvianolic acids among antioxidant polyphenols in comfrey (Symphytum officinale L.) roots', Food and Chemical Toxicology, 112, pp. 178-187. doi:10.1016/j.fct.2017.12.051 Preclinical
https://doi.org/10.1016/j.fct.2017.12.051 - Dey, D., Jingar, P., Agrawal, S., Shrivastava, V. and others (2019) 'Symphytum officinale augments osteogenesis in human bone marrow-derived mesenchymal stem cells in vitro as they differentiate into osteoblasts', Journal of Ethnopharmacology, 248, pp. 112329. doi:10.1016/j.jep.2019.112329 Preclinical
https://doi.org/10.1016/j.jep.2019.112329 - Kuchta, K. and Schmidt, M (2020) 'Safety of medicinal comfrey cream preparations (Symphytum officinale s.l.): The pyrrolizidine alkaloid lycopsamine is poorly absorbed through human skin', Regulatory Toxicology and Pharmacology, 118, pp. 104784. doi:10.1016/j.yrtph.2020.104784 Preclinical
https://doi.org/10.1016/j.yrtph.2020.104784 - European Medicines Agency (2011) 'European Union herbal monograph on Symphytum officinale L., radix'. Traditional / reference
https://scholar.google.com/scholar?q=European%20Union%20herbal%20monograph%20on%20Symphytum%20officinale%20L.%2C%20radix - Plants For A Future 'Symphytum officinale (Comfrey)'. Available at: https://pfaf.org/user/Plant.aspx?LatinName=Symphytum+officinale Traditional / reference
https://pfaf.org/user/Plant.aspx?LatinName=Symphytum+officinale - Royal Botanic Gardens, Kew (n.d.). Available at: https://powo.science.kew.org Traditional / reference
https://powo.science.kew.org - Staiger, C (2012) 'Comfrey: a clinical overview', 26(10), pp. 1441--1448. doi:10.1002/ptr.4612 Randomized trial
https://doi.org/10.1002/ptr.4612 - Duke, J.A (2002) 'Handbook of Medicinal Herbs, Second Edition'. Traditional / reference
https://scholar.google.com/scholar?q=Handbook%20of%20Medicinal%20Herbs%2C%20Second%20Edition - Vithayathil, M.K. and Edwards, M (2016) 'Comfrey herbal remedy causing second-degree heart block: do not be outfoxed by digitalis', BMJ Case Reports, 2016, pp. bcr2016216995. doi:10.1136/bcr-2016-216995 Clinical study
https://doi.org/10.1136/bcr-2016-216995 - Lin, C.C. and Yang, C.C. and Phua, D.H. and Deng, J.F. and Lu, L.H (2010) 'An outbreak of foxglove leaf poisoning', Journal of the Chinese Medical Association, 73(2), pp. 97-100. doi:10.1016/S1726-4901(10)70009-5 Clinical study
https://doi.org/10.1016/S1726-4901(10)70009-5 - Woodland Trust (2024) 'Foxglove (Digitalis purpurea)'. Available at: https://www.woodlandtrust.org.uk/trees-woods-and-wildlife/plants/wild-flowers/foxglove/ Traditional / reference
https://www.woodlandtrust.org.uk/trees-woods-and-wildlife/plants/wild-flowers/foxglove/
Selected studies & references
All 14 studies in the Knowledge Finder →
This profile is assembled automatically from the Omnia Sana plant database, which we curate by hand. How this site is built.