Arnica

Arnica (Arnica montana), also known as mountain arnica, is a medicinal plant found in Europe and North America in the Alps and other mountain regions. For centuries, Arnica has been used in traditional medicine, particularly for the treatment of bruises, muscle and joint pain, and inflammation. Its therapeutic properties are attributed primarily to the sesquiterpene lactones, flavonoids, and essential oils it contains.

What benefits can Arnica offer?

Arnica is used primarily for external application and is widely available in the form of creams, ointments, tinctures, and gels. The most common areas of use in which treatment can offer a benefit include:

  • Bruises and hematomas: Arnica is traditionally used for hematomas and bruises, as it can accelerate healing and reduce swelling (1,2).
  • Inflammation: Due to its anti-inflammatory properties, Arnica is often used for sprains, muscle strains, and joint pain. Studies have shown that helenalin reduces the activity of certain inflammation markers, which leads to pain relief (3,4,5).
  • Rheumatic complaints: For rheumatic conditions such as osteoarthritis, Arnica is used for the relief of joint pain and swelling. Some clinical studies suggest that Arnica can show an effect similarly good as that of nonsteroidal anti-inflammatory drugs (NSAIDs) in osteoarthritis (1,4,5,6).
  • Insect bites: Arnica is also used to relieve the itching and swelling of insect bites (7).

How does Arnica work?

Arnica works primarily through its anti-inflammatory and pain-relieving constituents such as helenalin and dihydrohelenalin. These compounds inhibit the production of prostaglandins and other pro-inflammatory substances in the body, which leads to a reduction in pain and swelling (1,8,9).

The most important bioactive constituents in Arnica are:

  • Helenalin: A sesquiterpene lactone that has anti-inflammatory effects and plays a central role in the plant's action.
  • Flavonoids: These have antioxidant effects and support the body's own defense mechanisms.
  • Essential oils: They contain, among other things, thymol, which has antiseptic properties.
  • Coumarins: These have anticoagulant properties, which can be beneficial for blood circulation.

Safety and side effects

Although Arnica offers many benefits, caution is advised, especially with internal use. Arnica is toxic in its raw form and must not be taken orally, as it can cause nausea, vomiting, cardiac arrhythmias, and severe poisoning (1). For external application it is generally safe, but allergic reactions can occur in people with sensitive skin. It is recommended to apply Arnica only to undamaged skin (1).

Interactions and precautions

  • Pregnancy and breastfeeding: Due to possible toxic effects, Arnica should not be taken or applied over large areas during pregnancy and breastfeeding.
  • Blood-thinning medications: People taking blood thinners should be careful when using Arnica, as it may potentially enhance the effect of such medications.

Conclusion

Arnica is a time-tested medicinal plant with strong anti-inflammatory, pain-relieving, and circulation-promoting properties. It is used successfully especially for bruises, hematomas, and rheumatic complaints. Due to its potential side effects, however, its use should be well dosed and above all external.

Sources

  1. Smith, A. G., Miles, V. N., Holmes, D. T., Chen, X., & Lei, W. (2021). Clinical Trials, Potential Mechanisms, and Adverse Effects of Arnica as an Adjunct Medication for Pain Management. Medicines (Basel, Switzerland), 8(10), 58. https://doi.org/10.3390/medicines8100058
  2. Jurcău R., Jurcău I. The effectiveness of Arnica Montana treatment, in sports post-trauma ankle sprains. Eficienţa tratamentului cu Arnica Montana, în entorse de gleznă post-traumatism sportive. Palestrica Third Millenn. Civiliz. Sport. 2013;14:33–39.
  3. Kriplani, P., Guarve, K., & Baghael, U. S. (2017). Arnica montana L. - a plant of healing: review. The Journal of pharmacy and pharmacology, 69(8), 925–945. https://doi.org/10.1111/jphp.12724
  4. Cameron, M., & Chrubasik, S. (2013). Topical herbal therapies for treating osteoarthritis. The Cochrane database of systematic reviews, 2013(5), CD010538. https://doi.org/10.1002/14651858.CD010538
  5. Knuesel, O., Weber, M., & Suter, A. (2002). Arnica montana gel in osteoarthritis of the knee: an open, multicenter clinical trial. Advances in therapy, 19(5), 209–218. https://doi.org/10.1007/BF02850361
  6. Widrig, R., Suter, A., Saller, R., & Melzer, J. (2007). Choosing between NSAID and arnica for topical treatment of hand osteoarthritis in a randomised, double-blind study. Rheumatology international, 27(6), 585–591. https://doi.org/10.1007/s00296-007-0304-y
  7. Huber, R., Bross, F., Schempp, C., & Gründemann, C. (2011). Arnica and stinging nettle for treating burns - a self-experiment. Complementary therapies in medicine, 19(5), 276–280. https://doi.org/10.1016/j.ctim.2011.08.001
  8. Lyss, G., Schmidt, T. J., Merfort, I., & Pahl, H. L. (1997). Helenalin, an anti-inflammatory sesquiterpene lactone from Arnica, selectively inhibits transcription factor NF-kappaB. Biological chemistry, 378(9), 951–961. https://doi.org/10.1515/bchm.1997.378.9.951
  9. Lyss, G., Knorre, A., Schmidt, T. J., Pahl, H. L., & Merfort, I. (1998). The anti-inflammatory sesquiterpene lactone helenalin inhibits the transcription factor NF-kappaB by directly targeting p65. The Journal of biological chemistry, 273(50), 33508–33516. https://doi.org/10.1074/jbc.273.50.33508
  10. Baillargeon, L., Drouin, J., Desjardins, L., Leroux, D., & Audet, D. (1993). Les effets de l'Arnica Montana sur la coagulation sanguine. Essai clinique randomisé [The effects of Arnica Montana on blood coagulation. Randomized controlled trial]. Canadian family physician Medecin de famille canadien, 39, 2362–2367.