# Arnica (Arnica montana) *Mountain tobacco, leopard’s bane; *Arnica montana* of Linnaeus; in pharmacy *Arnicae flos*, the flower* **Known today as.** *Arnica montana*, a perennial of the family Compositae native to the woods and mountain pastures of central Europe, found in England and southern Scotland but probably as an escape. Its leaves lie in a flat rosette from which a stalk one to two feet high bears orange-yellow flowers; the rhizome is dark brown, curved, with brittle wiry rootlets. The dried flower heads are the medicine now; Grieve’s pharmacopoeias used root and flower both. Kind: Plant Toxic: yes > **Caution.** For the skin only, and never on broken skin. Not for anyone sensitive to plants of the daisy family, Asteraceae, nor for children under twelve, nor in pregnancy, for want of data; itching, redness, and eczema may occur. LiverTox finds no liver injury from arnica used on the skin. Taken by mouth as a herb it is a poison: both Grieve and King’s record severe poisoning, and King’s a death. ## What was it used for? For bruises, outwardly. “In countries where Arnica is indigenous, it has long been a popular remedy,” Grieve wrote, and the tincture was laid on sprains, bruises, and wounds and painted on unbroken chilblains, though “Repeated applications may produce severe inflammation.” It was seldom given by mouth because it irritated the stomach; when it was, it was a stimulant and diuretic for low fevers and palsies. A footbath with the tincture eased tender feet, and applied to the scalp, she added, “it will make the hair grow.” ## What does modern science say? The European Medicines Agency’s herbal committee accepts the flower, applied to the skin, as a traditional herbal medicine, “exclusively based upon long-standing use,” for the relief of bruises, sprains, and localised muscular pain (monograph of 2014). Its assessment report names sesquiterpene lactones, helenalin and dihydrohelenalin and their esters, as the most relevant constituents, with flavonoids and essential oil. Most of the reviews of arnica trials read for this entry concern homeopathic preparations, which are not the herbal medicine of the monograph: a 1998 review of eight placebo-controlled trials of homeopathic arnica concluded that the claim of efficacy “beyond a placebo effect is not supported by rigorous clinical trials,” and a 2016 review of arnica and bromelain for bruising and swelling after procedures found “insufficient data to support use.” ## Pharmacognosy and toxicology - **helenalin**: a sesquiterpene lactone, with its esters among the most relevant constituents - **dihydrohelenalin**: a sesquiterpene lactone - **flavonoids**: - **essential oil**: **Mechanism.** Not established in the sources read for this entry. **Standing.** European Union herbal monograph (2014): traditional use on the skin, “exclusively based upon long-standing use,” for bruises, sprains, and localised muscular pain. Not for use by mouth. ## What lore surrounds it? Grieve warns that the flowers were often adulterated with other composite flowers, marigold among them, and that “some people are particularly sensitive to the plant and many severe cases of poisoning have resulted from its use, especially if taken internally.” The homeopaths took it up too: she records a homeopathic tincture used for epilepsy and for seasickness. ## What did the older authorities say? **King’s American Dispensatory.** “Locally arnica is irritant, the preparations of the flowers being most powerful,” and “Even when used as a local dressing for wounds dangerous inflammation, with vesication, has occurred.” Taken in large doses it caused heat in the throat, vomiting, purging, spasms, laboured breathing, and coma; King’s knew no antidote and records a death from the tincture. ## Sources - Grieve, M. *A Modern Herbal*, “Arnica.” As published on botanical.com. - Felter, H. W., & Lloyd, J. U. (1898). *King’s American Dispensatory*, vol. 1, “Arnica.” Internet Archive, kingsamericandis01kinguoft. - European Medicines Agency, Committee on Herbal Medicinal Products. *European Union herbal monograph on Arnicae flos (Arnica flower)*. EMA/HMPC/198793/2012, 6 May 2014. - European Medicines Agency, Committee on Herbal Medicinal Products. *Assessment report on Arnicae flos*. EMA/HMPC/198794/2012, 6 May 2014. - Ernst E & Pittler MH (1998). Efficacy of homeopathic arnica: a systematic review of placebo-controlled clinical trials. *Archives of surgery (Chicago, Ill. : 1960)*. PMID 9820349. - Ho D, et al. (2016). Is There a Role for Arnica and Bromelain in Prevention of Post-Procedure Ecchymosis or Edema? A Systematic Review of the Literature. *Dermatologic surgery : official publication for American Society for Dermatologic Surgery [et al.]*. PMID 27035499. - LiverTox: Clinical and Research Information on Drug-Induced Liver Injury, “Arnica Montana.” National Institute of Diabetes and Digestive and Kidney Diseases, updated 2023. NCBI Bookshelf. - European Medicines Agency, Committee on Herbal Medicinal Products. *European Union herbal monograph on Arnicae flos (Arnica flower)*. EMA/HMPC/198793/2012, 6 May 2014. - European Medicines Agency, Committee on Herbal Medicinal Products. *Assessment report on Arnicae flos*. EMA/HMPC/198794/2012, 6 May 2014. - LiverTox: Clinical and Research Information on Drug-Induced Liver Injury, “Arnica Montana.” National Institute of Diabetes and Digestive and Kidney Diseases, updated 2023. NCBI Bookshelf. --- *Arnica.* In *Materia Medica*, edited by B. C. P. Statema. Version 1, revised 2026-10-16. The Thinking Press. https://thethinkingpress.org/materia-medica/arnica Historical description, not medical advice.