Related Terms

  • 6-methoxykaempferol, Aconitum napellus, alisma, American arnica, Arnica augustifolia, Arnica chamissonis, Arnica cordifolia, arnica da serra, arnica flower, Arnica fulgens, Arnica latifolia, Arnica lonchophylla, Arnica montana, arnica root, Arnica sororia, arnica spray, Arnicae flos, arnicaid, arniflora, arnika, Arnikablüten, Asteraceae (family), bergwohlverleih, bétoine des montagnes, betuletol, bilmes herb, Caltha alpina, chamissonolid, common arnica, Compositae (family), donnerblume, engel trank, European arnica, fallherb, fallkraut, flavonoids, fleurs d’arnica, guldblomme, helenalin, herbe aux chutes, hispidulin, jaceosidin, kraftwurz, leopard’s bane, lignans, monkshood, mountain arnica, mountain daisy, mountain snuff, mountain tobacco, pectolinarigenin, polmonaria di montagna, prickherb, sesquiterpene lactones, SinEcch, smokeherb, sneezewort, snuffplant, souci des alpes, Spanish flower heads, St. John’s strength flower, strengthwort, tabac des Vosges, tabaco de montana, thunderwort, waldblume, wellbestow, wolfesgelega, wolf’s bane, wolf’s eye, wolf’s yellow, wolfsbane, wolfsblume, wolfstoterin, woundherb, wundkraut.
  • Note: This monograph does not include Heterotheca incloides (Mexican arnica).


  • Arnica montana is commonly used in herbal ointments and oils applied on the skin as an anti-inflammatory and pain-relieving agent for aches, bruises, and sprains on unbroken skin. Highly diluted homeopathic preparations are considered safe and are widely used for the treatment of injuries. However, full doses of arnica may be toxic when taken by mouth. Arnica may also be damaging to the heart, resulting in high blood pressure.
  • The U.S. Food and Drug Administration (FDA) has declared arnica an unsafe herb due to adverse effects reported when taken by mouth. In contrast, the German market offers over 100 preparations of arnica to its consumers. In Canada, arnica is not allowed for use as a non-medicinal ingredient for oral (by mouth) use products.

Evidence Table


    These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.


    Homeopathic and topical (on the skin) arnica is widely used to prevent or treat hemorrhages (heavy bleeding), hematomas (blood clots), and bruising. More study is needed in this area to draw a firm conclusion.

    Coagulation (blood clotting)

    Homeopathic arnica does not seem to affect bleeding time or platelet count. More studies are needed in this area.

    Diabetic retinopathy

    Homeopathic arnica has been used for improving retinal microcirculation, thereby slowing the progression of damage to the retina of the eye in diabetics. Although early study is promising, additional study is needed before a firm conclusion can be reached.

    Diarrhea in children (acute)

    Arnica has not been well studied for its effects on diarrhea, but early study suggests that homeopathic arnica may decrease the duration of diarrhea in children. Further study is needed to make a strong recommendation.

    Ileus (postoperative)

    Postoperative ileus is characterized by a temporary impairment of gastrointestinal motility. Symptoms may include abdominal pain, nausea and vomiting, reduced desire to eat, and an inability to pass gas or stool. There is early evidence that homeopathic arnica treatment may reduce the duration of ileus after abdominal or gynecologic surgery. Well-designed research is needed to make a strong recommendation.


    Arnica gel has been used on the skin for osteoarthritis pain and stiffness, due to its anti-inflammatory constituents. Although early study is promising, additional study is needed.

    Pain (post-operative)

    Some patients use homeopathic arnica to relieve pain after an operation. However, arnica is often used with other pain-relieving agents. It is unclear how effective arnica is alone for the treatment of pain.


    Homeopathic arnica has been used in stroke recovery. More research is needed before a firm recommendation can be made.


    Many patients use arnica to relieve pain postoperatively. Further study is needed to define the effectiveness of arnica in postoperative pain.

    Muscle soreness

    Homeopaths believe that arnica may be effective in relieving pain due to delayed onset muscle soreness, which is defined by exercise to which subjects are unaccustomed. Currently, it is not recommended to give arnica for this indication, although it does not appear to be unsafe for use.

*Key to grades:



    The below uses are based on tradition, scientific theories, or limited research. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider. There may be other proposed uses that are not listed below.



    The below doses are based on scientific research, publications, traditional use, or expert opinion. Many herbs and supplements have not been thoroughly tested, and safety and effectiveness may not be proven. Brands may be made differently, with variable ingredients, even within the same brand. The below doses may not apply to all products. You should read product labels, and discuss doses with a qualified healthcare provider before starting therapy.

  • Adults (18 years and older)

    • Arnica is toxic if taken internally except when diluted into homeopathic preparations. Homeopathic treatment is usually individualized to correspond specifically to the patient’s symptoms. Typical homeopathic dosing uses either 5C or 30C potency tablets sublingually (under the tongue) three times a day. Doses can be taken for 24 hours or up to six months, although a qualified healthcare practitioner, including a pharmacist, should be consulted before making decisions about dosing.
    • Other forms of arnica dosing include tinctures taken by mouth, or ointments and fresh plant gel applied on the skin. There is not enough scientific evidence to give specific doses or times for these forms.
  • Children (younger than 18 years)

    • There is no proven safe or effective dose of arnica in children.



    The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.

  • Allergies

    • Avoid in individuals with a known allergy or hypersensitivity to arnica or any member of the Asteraceae or Compositae families. Possible cross-sensitivity can occur in those allergic to the Asteraceae or Compositae family (Achillea millefolium, Ambrosia species, Anthemis cotula asters, calendula, chamomile, chrysanthemum, dahlia, daisy, dandelion, dog fennel chicory, Matricaria chamomilla, mugwort, marigold, May weed, sunflower, tansy, and yarrow).
  • Side Effects and Warnings

    • Arnica is likely safe when used short-term in oral or sublingual (under tongue) homeopathic doses. It is possibly safe when applied topically/externally to unbroken skin for short-term use. Arnica is likely unsafe when taken by mouth in doses higher than homeopathic dilutions. It may also be unsafe when used topically (on the skin) long-term. Using full strength tinctures on hypersensitive or broken skin is also not recommended.
    • Ingestion of arnica extracts has been known to increase heartbeat and increase bleeding time.
    • Allergic reactions may occur when taking arnica in full strength preparations or when handling the plant. Reactions including Sweet’s syndrome, facial eczema, oral lesions (mouth wounds), itchy erythema (reddening of the skin) of the legs, trunk (torso), and face, and dermatitis.
    • Taking Arnica montana-containing extracts by mouth has caused severe gastroenteritis (inflammation of the stomach), including gastrointestinal problems due to mucosal irritation nervousness, nausea, and vomiting.
    • Arnica may also cause muscle weakness, collapse, and death. High doses may impair urine flow and damage the kidneys and liver. There is also the potential for organ damage, coma, and death with the internal use of arnica.
  • Pregnancy and Breastfeeding

    • Internal use of arnica is not recommended in pregnant women due to the potential for uterine stimulation and toxicity. Avoid if breastfeeding.



    Most herbs and supplements have not been thoroughly tested for interactions with other herbs, supplements, drugs, or foods. The interactions listed below are based on reports in scientific publications, laboratory experiments, or traditional use. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy.

  • Interactions with Drugs

    • Arnica may interact with anesthetic (pain-reducing) drugs, corticosteroids, or anti-inflammatories; reduce the effectiveness of blood pressure-lowering drugs; and/or enhance bleeding if taken with other anticoagulants (blood thinners). Caution is advised.
    • Arnica applied to the skin may increase hydroxyethyl salicylate’s analgesic (pain-relieving) effect.
    • Certain constituents found in arnica may lower serum lipids. Caution is advised in those patients taking cholesterol-lowering medications.
  • Interactions with Herbs and Dietary Supplements

    • Arnica may interact with herb or supplements with anesthetic (pain-reducing), steroid, or anti-inflammatory effects.
    • Arnica may increase the risk of bleeding when taken with drugs that increase the risk of bleeding. Multiple cases of bleeding have been reported with the use of Ginkgo biloba, and fewer cases with garlic and saw palmetto.
    • Arnica use may reduce the effectiveness of blood pressure-lowering herbs and supplements.
    • Arnica used with daisy (Bellis perennis) may reduce postpartum blood loss. A qualified healthcare practitioner, including a pharmacist, should be consulted before combining herbs and supplements.


  • This information is based on a systematic review of scientific literature edited and peer-reviewed by contributors to the Natural Standard Research Collaboration ().



    Natural Standard developed the above evidence-based information based on a thorough systematic review of the available scientific articles. For comprehensive information about alternative and complementary therapies on the professional level, go to . Selected references are listed below.

  • Baillargeon L, Drouin J, Desjardins L, et al. The effects of arnica montana on bleeding time: a randomized clinical trial. Biomedical Therapy 1998;16(4):272-276.
  • Bergonzi MC, Bilia AR, Casiraghi A, et al. Evaluation of skin permeability of sesquiterpenes of an innovative supercritical carbon dioxide Arnica extract by HPLC/DAD/MS. Pharmazie 2005;60(1):36-38.
    View Abstract
  • Brinkhaus B, Wilkens JM, Ludtke R, et al. Homeopathic arnica therapy in patients receiving knee surgery: results of three randomised double-blind trials. Complement Ther Med. 2006 Dec;14(4):237-46.
    View Abstract
  • Cuzzolin L, Zaffani S, Benoni G. Safety implications regarding use of phytomedicines. Eur J Clin Pharmacol 2006;62(1):37-42.
    View Abstract
  • Hart O, Mullee MA, Lewith G, et al. Double-blind, placebo-controlled, randomized clinical trial of homoeopathic arnica C30 for pain and infection after total abdominal hysterectomy. J R Soc Med 1997;90(2):73-78.
    View Abstract
  • Knuesel O, Weber M, Suter A. Arnica montana gel in osteoarthritis of the knee: an open, multicenter clinical trial. Adv Ther 2002;19(5):209-218.
    View Abstract
  • Kos O, Lindenmeyer MT, Tubaro A, et al. New sesquiterpene lactones from Arnica tincture prepared from fresh flowerheads of Arnica montana. Planta Med 2005;71(11):1044-1052.
    View Abstract
  • Oberbaum M, Galoyan N, Lerner-Geva L, et al. The effect of the homeopathic remedies Arnica montana and Bellis perennis on mild postpartum bleeding–a randomized, double-blind, placebo-controlled study–preliminary results. Complement Ther Med 2005;13(2):87-90.
    View Abstract
  • Raschka C, Trostel Y. Effect of a homeopathic arnica preparation (D4) on delayed onset muscle soreness. Placebo-controlled crossover study. MMW Fortschr Med. 2006 Jul 20;148(29-30):35.
    View Abstract
  • Robertson A, Suryanarayanan R, Banerjee A. Homeopathic Arnica montana for post-tonsillectomy analgesia: a randomized placebo control trial. Homeopathy. 2007 Jan;96(1):17-21.
    View Abstract
  • Seeley BM, Denton AB, Ahn MS, et al. Effect of homeopathic Arnica montana on bruising in face-lifts: results of a randomized, double-blind, placebo-controlled clinical trial. Arch Facial Plast Surg 2006;8(1):54-59.
    View Abstract
  • Stevinson C, Devaraj VS, Fountain-Barber A, et al. Homeopathic arnica for prevention of pain and bruising: randomized placebo-controlled trial in hand surgery. J R Soc Med 2003;96(2):60-65.
    View Abstract
  • Totonchi A, Guyuron B. A randomized, controlled comparison between arnica and steroids in the management of postrhinoplasty ecchymosis and edema. Plast Reconstr Surg. 2007 Jul;120(1):271-4.
    View Abstract
  • Tuten C, McClung J. Reducing muscle soreness with Arnica montana: Is it effective? Alternative and Complementary Therapies 1999;5(6):369-372.
  • Vickers AJ, Fisher P, Smith C, et al. Homeopathic Arnica 30x is ineffective for muscle soreness after long- distance running: a randomized, double-blind, placebo-controlled trial. Clin J Pain 1998;14(3):227-231.
    View Abstract