Herbal Monograph
Arnica
Arnica montana L.
Asteraceae (Compositae)
Premier topical anti-inflammatory for bruises, sprains, and trauma recovery -- EXTERNAL USE ONLY. Helenalin potently...
Overview
Plant Description
Arnica montana is a perennial herbaceous plant growing 20-60 cm (8-24 inches) tall from a short, stout, dark brown rhizome. It produces a basal rosette of 4-8 broadly ovate to lanceolate leaves that are slightly hairy on the upper surface, prominently veined, and 5-17 cm long, arranged in opposite pairs flat against the ground. The flowering stem is erect, slightly hairy and glandular, bearing 1-3 pairs of smaller opposite stem leaves. The stem terminates in a single (occasionally 2-3) bright golden-yellow daisy-like flower head (capitulum), 6-8 cm in diameter. Each flower head consists of 12-20 spreading ray florets (each 2-3 cm long, irregularly toothed at the tip) surrounding a dense central disc of numerous orange-yellow tubular florets. The entire flower head is aromatic with a distinctive, pleasant, somewhat camphoraceous scent. The involucral bracts are lanceolate, hairy, and arranged in two rows. The fruit is an achene (cypsela) approximately 5-7 mm long, dark, ribbed, with a pappus of rough, white hairs for wind dispersal. The plant has a characteristic appearance that is unmistakable in its native alpine meadow habitat. The species epithet 'montana' refers to its mountain habitat, and the genus name 'Arnica' may derive from the Greek 'arnakis' (lambskin), referring to the soft, hairy leaf texture.
Habitat
Arnica montana is a characteristic species of nutrient-poor, acidic to neutral (pH 4.5-6.5), well-drained mountain meadows and pastures in the subalpine and alpine zones of Europe, typically at elevations of 500-2,800 meters. It thrives in unimproved, extensively managed grasslands -- particularly those with low nitrogen input -- and is associated with Nardus stricta (mat-grass) communities, hay meadows (Arrhenatherion), and heathland margins. The species requires full sun to light shade and is intolerant of heavy fertilization, intensive grazing, and soil compaction. It prefers siliceous (non-calcareous) substrates, though it can occasionally occur on mildly calcareous soils. CONSERVATION STATUS: Arnica montana is listed on Annex V of the EU Habitats Directive (species whose exploitation requires management measures) and is protected by national legislation in many European countries including Germany, France, Switzerland, Austria, and several Scandinavian nations. Wild populations have declined dramatically over the past century due to agricultural intensification (fertilization of meadows), abandonment of traditional extensive grazing practices, land-use changes, habitat loss, and historical over-collection. The species is classified as 'Least Concern' globally by IUCN but is nationally endangered or vulnerable in many parts of its range. Wild collection for commercial purposes is now heavily restricted or banned in most European countries.
Distribution
Native to the mountains of Europe, with a distribution centered on the Alpine arc extending into the Pyrenees, Carpathians, Scandinavian mountains, and upland areas of the British Isles (rare and declining). The core range includes the Alps (France, Switzerland, Austria, Italy, Slovenia), Pyrenees (Spain, France), Carpathians (Romania, Poland, Slovakia, Ukraine), and montane regions of Germany, Czech Republic, and Scandinavia (Norway, Sweden, Finland). Isolated populations exist in the Baltic states, southern Portugal, and the Balkans. The species is absent from the Mediterranean lowlands and does not occur naturally outside Europe. Arnica montana is NOT native to North America, though several related Arnica species (A. chamissonis, A. fulgens, A. cordifolia, A. sororia) are indigenous to the continent.
Parts Used
Flower heads (Arnicae flos)
Preferred: Dried flower heads for tincture preparation (external use), oil infusion, or incorporation into topical preparations (gels, creams, ointments)
The dried flower heads (capitula) are the primary pharmacopeial drug recognized by the European Pharmacopoeia (Ph. Eur.), German Pharmacopoeia (DAB), and Commission E. They contain the highest concentration of sesquiterpene lactones (helenalin and its esters), the principal active constituents responsible for anti-inflammatory and analgesic effects. The flower heads are the basis for virtually all official and traditional topical preparations. The European Pharmacopoeia monograph 'Arnicae flos' specifies quality criteria including minimum sesquiterpene lactone content (not less than 0.4% calculated as helenalin tiglinate for A. montana, not less than 0.25% for A. chamissonis). Whole dried flower heads, including both ray and disc florets plus involucral bracts, constitute the drug.
Rhizome and roots (Arnicae radix)
Preferred: Dried rhizome for tincture or decoction (traditional use; external application)
The rhizome was historically used in European folk medicine, particularly in Germany and Scandinavia, as a masticatory and for respiratory conditions. It contains thymol and thymol derivatives (thymol methyl ether) as major essential oil components, along with sesquiterpene lactones (though at different concentrations and ratios than the flowers). The rhizome drug (Arnicae radix) is recognized in some older pharmacopeias but is not the primary commercial drug today. Its use has largely been superseded by the flower head preparations. It is less frequently available commercially.
Whole herb (Arnicae herba)
Preferred: Fresh or dried whole herb for external poultice (folk use)
The aerial parts (leaves and stems with flowers) have been used in some traditional preparations, particularly in folk medicine. The leaves contain sesquiterpene lactones and other active constituents but at lower concentrations than the flower heads. Not a standard pharmacopeial preparation. Occasionally referenced in ethnobotanical literature for poultice applications.
Key Constituents
Sesquiterpene lactones (pseudoguaianolides)
The sesquiterpene lactones, especially helenalin and its esters, are unequivocally the primary pharmacologically active constituents of arnica, responsible for its well-established topical anti-inflammatory and analgesic effects. The NF-kB inhibitory mechanism of helenalin (IC50 approximately 5-10 microM in cell-based assays) explains the broad anti-inflammatory action observed clinically: reduction of swelling, pain, and bruising following trauma, sprains, and surgery. The same reactive alpha-methylene-gamma-butyrolactone moiety that confers anti-inflammatory potency also underlies the toxicity of helenalin when taken internally (cytotoxic to gastric mucosa, hepatotoxic, cardiotoxic at sufficient doses) and the allergic contact dermatitis risk in sensitized individuals. This dual nature -- potent topical therapeutic but dangerous internal toxin -- is the defining pharmacological characteristic of arnica. European Pharmacopoeia quality standards for Arnicae flos are based on minimum sesquiterpene lactone content, confirming their centrality to therapeutic activity.
Flavonoids
Flavonoids contribute antioxidant activity (free radical scavenging, metal chelation), anti-inflammatory effects (inhibition of lipoxygenase and hyaluronidase), and capillary-stabilizing (venotonic) properties that complement the sesquiterpene lactone-mediated anti-inflammatory action. The capillary-stabilizing effect of flavonoids is particularly relevant to arnica's traditional use for bruising, as it may help reduce capillary fragility and extravasation. Flavonoids also provide UV-protective and wound-healing supportive activity in topical preparations.
Essential oil (volatile terpenoids)
The essential oil contributes antimicrobial (antiseptic) activity relevant to wound care applications, mild local anesthetic and counterirritant effects that complement the anti-inflammatory action of sesquiterpene lactones, and the characteristic pleasant aroma of arnica preparations. Thymol is specifically recognized for its antimicrobial properties against a broad spectrum of bacteria and fungi.
Phenolic acids (hydroxycinnamic acid derivatives)
Phenolic acids provide broad-spectrum antioxidant activity through free radical scavenging and metal chelation. Chlorogenic acid and caffeic acid derivatives contribute to anti-inflammatory and tissue-protective effects in topical applications. They play a supportive role alongside the primary sesquiterpene lactone activity.
Coumarins
Coumarins make a minor contribution to the anti-inflammatory and spasmolytic properties of arnica preparations. Their presence is of more significance for phytochemical characterization than for therapeutic effect at the concentrations found in arnica flower extracts.
Polysaccharides
Polysaccharides contribute immunostimulating and wound-healing supportive activity, particularly relevant in topical applications where they may enhance local immune surveillance and tissue repair processes. Their role is secondary to the sesquiterpene lactones in the overall therapeutic profile of arnica.
Carotenoids and lipophilic pigments
Triterpene diols (arnidiol, faradiol) are increasingly recognized as important contributors to arnica's topical anti-inflammatory activity, complementing the sesquiterpene lactone mechanism through different pathways. Faradiol and arnidiol demonstrate anti-edema and anti-inflammatory effects in animal models. Their contribution is most significant in lipophilic preparations (oils, ointments) that efficiently extract these compounds.
Herbal Actions
The primary and best-established pharmacological action of arnica. Helenalin and its esters potently inhibit NF-kB activation by alkylating the p65 (RelA) subunit at Cys38, preventing nuclear translocation and DNA binding. This blocks transcription of multiple pro-inflammatory mediators simultaneously: TNF-alpha, IL-1beta, IL-6, IL-8, COX-2, iNOS, and adhesion molecules (ICAM-1, VCAM-1, E-selectin). Additionally, helenalin directly inhibits 5-lipoxygenase and impairs neutrophil chemotaxis and oxidative burst. Faradiol and arnidiol (triterpene diols) provide complementary anti-inflammatory activity via anti-edema effects. Flavonoids contribute antioxidant and hyaluronidase-inhibitory activity. German Commission E approved arnica for 'external use for treatment of injuries and consequences of accidents, e.g., hematoma, dislocations, contusions, edema associated with fractures, and for rheumatic muscle and joint complaints.' CRITICAL DISTINCTION: This anti-inflammatory action is for EXTERNAL (topical) use only. Internal administration of arnica herb preparations is toxic and NOT therapeutically indicated.
[1, 2, 5, 10, 11]Topical arnica preparations demonstrate clinically significant pain reduction in bruising, sprains, strains, and osteoarthritis. The analgesic effect is mediated by: (1) inhibition of NF-kB-dependent inflammatory pain mediators; (2) inhibition of prostaglandin and leukotriene biosynthesis (via COX-2 and 5-LOX inhibition); (3) mild counterirritant effect of the essential oil components (thymol); (4) reduction of edema and tissue pressure. The Widrig et al. (2007) RCT demonstrated that topical arnica gel was comparable to ibuprofen gel in reducing pain and improving function in hand osteoarthritis, providing the strongest clinical evidence for arnica's analgesic action.
[1, 2, 4, 7]Arnica promotes wound healing and tissue repair when applied topically to unbroken skin. Mechanisms include: stimulation of macrophage phagocytic activity by polysaccharides, enhanced granulocyte migration to injury sites, antioxidant protection of regenerating tissue by flavonoids, and antimicrobial activity of thymol. Commission E and EMA endorse arnica for contusions and hematoma resolution. IMPORTANT: Arnica should NOT be applied to open, broken, or abraded skin, as sesquiterpene lactones can cause significant local irritation and delayed wound healing on raw wounds.
[1, 2, 4]The essential oil component, particularly thymol and its derivatives, provides mild antimicrobial activity against common wound-infecting bacteria (Staphylococcus aureus, Streptococcus spp.) and dermatophyte fungi. This antiseptic action supports arnica's traditional use in wound care and its Commission E-approved indication as a mouth rinse for inflammation of the mucous membranes (stomatitis, gingivitis). The antimicrobial activity is supportive rather than primary and is not sufficient for treatment of established infection.
[1, 4]Topical application of arnica preparations causes mild local hyperemia (increased blood flow to the application area) through a counterirritant mechanism. This increased local circulation supports resolution of bruising (hematoma) by enhancing reabsorption of extravasated blood and tissue fluids. The rubefacient effect is mild at typical concentrations but contributes to arnica's efficacy in resolving bruises and ecchymoses. Flavonoids contribute capillary-stabilizing (venotonic) effects that reduce further capillary leakage.
[4, 5]Arnica acts as a mild counterirritant when applied to the skin, producing gentle warming and increased local blood flow without the intense irritation caused by stronger rubefacients (e.g., capsaicin, mustard). The counterirritant effect is mediated primarily by the essential oil components (thymol derivatives) and to a lesser extent by the sesquiterpene lactones. This mechanism provides sensory pain relief through gate-control theory (competing sensory input) and supports resolution of deep tissue bruising by enhancing superficial circulation.
[4, 5]Therapeutic Indications
Musculoskeletal System
Bruising and contusions (ecchymoses)
This is the most well-established and widely recognized indication for topical arnica. German Commission E approved arnica for 'external use for treatment of injuries and consequences of accidents, e.g., hematoma.' The EMA classified topical arnica preparations as 'well-established use' for bruising. Multiple clinical studies support efficacy. Mechanism: NF-kB inhibition reduces inflammatory response to tissue trauma; circulatory stimulation enhances reabsorption of extravasated blood; flavonoid capillary-stabilizing effects reduce ongoing capillary leakage. Arnica gel, cream, ointment, or diluted tincture compress applied to the bruised area (with intact skin) 2-3 times daily. Homeopathic Arnica (30C, 200C) is also extremely widely used for bruising, though evidence for homeopathic preparations is distinct from herbal evidence.
[1, 2, 4, 5]Sprains, strains, and soft tissue injuries
Commission E and EMA both approve arnica for 'dislocations' and 'sprains.' Topical arnica reduces swelling, pain, and inflammation associated with ligament sprains, muscle strains, and other soft tissue injuries. Applied as gel, cream, or diluted tincture compress to the affected area. Particularly valued in sports medicine for acute injuries where skin is intact. Zafra et al. (2010) demonstrated reduced markers of muscle damage and inflammation following eccentric exercise with topical arnica application.
[1, 2, 4]Osteoarthritis (particularly hand and knee OA)
Widrig et al. (2007) conducted a rigorous randomized, double-blind RCT comparing arnica gel (A. montana fresh plant 50 g/100 g gel) with ibuprofen 5% gel in 204 patients with radiologically confirmed hand osteoarthritis over 3 weeks. Results: arnica gel was non-inferior to ibuprofen gel for pain reduction (VAS), hand function (HAQ-DI), and grip strength. Both treatments significantly improved all outcomes from baseline. Adverse events were similar between groups. This landmark study provided Level I evidence that topical arnica is a viable alternative to topical NSAIDs for hand OA. Knuesel et al. (2002) similarly reported that arnica gel improved pain and stiffness scores in knee OA patients. These findings are clinically significant as they demonstrate arnica's utility beyond acute trauma to chronic inflammatory joint conditions.
[2, 7, 8]Post-surgical swelling and pain reduction
Multiple clinical trials have investigated arnica (both herbal and homeopathic preparations) for post-surgical recovery. Noteworthy studies: (1) Totonchi and Guyuron (2007): RCT in rhinoplasty patients found perioperative arnica significantly reduced post-operative ecchymosis. (2) Brinkhaus et al. (2006): RCT found topical arnica reduced knee swelling after arthroscopy. (3) Leu et al. (2010): RCT demonstrated reduced ecchymosis and post-procedural pain following laser treatment. Post-surgical arnica use is common in plastic surgery and sports medicine. Evidence is strongest for reducing bruising and ecchymosis; effects on pain and edema are more variable across studies. The EMA recognizes traditional use for 'minor injuries' which encompasses post-surgical bruising.
[2, 5]Rheumatic muscle and joint complaints
Commission E specifically approved arnica for 'rheumatic muscle and joint complaints.' This encompasses myalgia, arthralgia, and non-specific musculoskeletal pain of inflammatory origin. The anti-inflammatory mechanism (NF-kB inhibition) is directly relevant to rheumatic inflammation. Applied topically as gel, cream, ointment, or diluted tincture compress. Well-suited for localized pain conditions accessible to topical application.
[1, 2, 4]Post-exercise muscle soreness (delayed onset muscle soreness, DOMS)
Several studies have investigated topical or oral homeopathic arnica for exercise-induced muscle soreness. Results are mixed: some studies show modest reduction in subjective soreness and creatine kinase levels, while others find no significant benefit. Topical arnica application to muscles after intense exercise is widely practiced in sport. The anti-inflammatory and circulatory-stimulant mechanisms are pharmacologically plausible for this indication. More rigorous trials specific to topical herbal (non-homeopathic) arnica are needed.
[2]dermatological
Superficial phlebitis and varicosities (topical)
Traditional use of topical arnica for superficial venous inflammation and varicose veins. The combination of anti-inflammatory (NF-kB inhibition), capillary-stabilizing (flavonoids), and circulatory-stimulant actions provides pharmacological rationale. Applied as diluted tincture compress or gel to the affected area. Limited clinical trial evidence specific to this indication.
[4, 5]Insect bites and stings (topical, unbroken skin)
Traditional application of arnica preparations to insect bites and stings to reduce swelling, redness, and itching. The anti-inflammatory and mild antiseptic actions are relevant. Apply to intact skin only -- do not apply to broken or heavily scratched skin. Folk use is well-documented but formal clinical trials for this specific indication are lacking.
[4]Acne and boils (topical)
Traditional use of dilute arnica preparations for inflammatory skin conditions including acne and boils. The anti-inflammatory and antiseptic (thymol) actions provide pharmacological rationale. Use requires caution as arnica can cause contact dermatitis in sensitized individuals. Not a first-line treatment for acne in modern herbal practice. Apply only to intact skin.
[4]oral-mucosal
Stomatitis and gingivitis (as mouth rinse)
German Commission E specifically approved arnica as a mouth rinse for 'inflammation of the mucous membranes of the mouth and throat.' The preparation is a diluted tincture used as a gargle or rinse (NOT swallowed). The anti-inflammatory (helenalin), antiseptic (thymol), and vulnerary actions are all relevant to oral mucosal inflammation. Preparation: dilute arnica tincture (1:5-1:10 in water) used as a gargle or mouth rinse 2-3 times daily. IMPORTANT: The rinse must NOT be swallowed. This represents a legitimate non-topical external use that takes advantage of mucosal anti-inflammatory effects without systemic absorption.
[1, 2, 4]note-on-internal-use
INTERNAL USE: TOXIC -- Herbal preparations must NOT be taken internally
CRITICAL SAFETY INFORMATION: Internal (oral) use of Arnica montana herbal preparations (tincture, tea, extract) is TOXIC and is NOT therapeutically indicated. Helenalin is a potent cytotoxin that causes severe gastroenteritis (nausea, vomiting, abdominal pain, bloody diarrhea), tachycardia, cardiac arrhythmias, muscular weakness and paralysis, hepatotoxicity, renal damage, coma, and death at sufficient doses. The lethal dose in humans is estimated at approximately 70 g of flower heads or equivalent extract. Even sub-lethal doses can cause significant organ damage. Commission E, EMA, WHO, and all modern pharmacopeial authorities restrict arnica to EXTERNAL use only. The SOLE exception to internal use is in HOMEOPATHIC dilutions (6C and above), where the original plant material has been diluted beyond any pharmacologically active concentration. Homeopathic Arnica (Arnica montana 30C, 200C, etc.) is one of the most popular and widely used homeopathic remedies worldwide, used for trauma, bruising, surgical recovery, and emotional shock. However, homeopathic preparations are pharmacologically distinct from herbal preparations and do not contain measurable quantities of helenalin.
[1, 2, 3, 4, 5, 6]Energetics
Temperature
warm
Moisture
dry
Taste
Tissue States
cold/depression, damp/stagnation
In the Western herbal energetic framework, arnica is classified as warm and dry, with pungent and bitter tastes. The warming, stimulating quality is evident in its topical counterirritant effect -- arnica increases local blood flow and metabolic activity in the tissue to which it is applied. The pungency reflects its dispersive, circulatory-stimulating nature, while the bitterness corresponds to its sesquiterpene lactone content. Arnica addresses cold/depressed tissue states (stagnant bruising, sluggish resolution of trauma, poor local circulation) and damp/stagnant states (edema, swelling, fluid accumulation following injury). It is a tissue-stimulant that moves stagnant blood and fluid out of damaged tissues. Matthew Wood describes arnica as acting on 'bruised, shocked, or traumatized' tissues, restoring circulation and sensation to areas of injury. In the Eclectic tradition, arnica was considered specific for 'recent injuries with bruised, sore feeling' and for 'nervous shock from injury.' The warming, dispersing energetic profile makes arnica most appropriate for acute cold/stagnant presentations (fresh bruises, cold swelling) rather than hot/inflamed conditions. CAVEAT: Herbal energetics are interpretive frameworks within Western herbalism and are not standardized across all practitioners. The energetic assessment pertains to topical application; internal use is toxic and not therapeutically relevant.
Traditional Uses
European folk medicine (Alpine tradition, Central Europe)
- Topical application of bruised fresh flowers or flower poultice directly to bruises, sprains, and contusions -- one of the most iconic folk remedies of the European Alps
- Arnica-infused oil (flowers macerated in olive or sunflower oil) rubbed into sore muscles, stiff joints, and areas of rheumatic pain
- Arnica tincture (Arnikatinktur) diluted with water and applied as a compress to swellings, sprains, and post-injury inflammation -- a household staple in German-speaking countries
- Gargle with diluted arnica tincture for sore throat and inflamed gums
- Smoking of dried arnica leaves as a tobacco substitute (hence the name 'Mountain Tobacco' or 'Bergwohlverleih') -- a historical folk practice, not therapeutically indicated
- Internal use of arnica tea (Arnikatee) was historically practiced in some folk traditions for digestive stimulation and uterine complaints, but this practice was abandoned as the toxicity of internal use became recognized
"Arnica has been a cornerstone of European folk medicine for centuries, particularly in the Alpine regions of Germany, Austria, Switzerland, and France. The 12th-century Abbess Hildegard of Bingen referenced arnica for bruising. By the 16th-17th centuries, arnica was one of the most widely used wound remedies in German folk medicine. Johann Wolfgang von Goethe reportedly used arnica tea for his angina, though this internal use is now understood to be dangerous. The German folk name 'Wohlverleih' (bestower of well-being) reflects its central status in traditional Alpine medicine. The folk practice of applying fresh bruised arnica flowers directly to injuries remains common in rural Alpine communities to this day."
German phytotherapy and Commission E tradition
- External application for injuries: hematoma, dislocations, contusions, edema associated with fractures (Commission E positive monograph, 1990)
- External application for rheumatic muscle and joint complaints
- Inflammation of the mucous membranes of the mouth and throat (as a mouth rinse with diluted tincture)
- Furunculosis (boils) -- external application
- Inflammation due to insect bites -- external application
- Superficial phlebitis -- external application
"The German Commission E issued a positive monograph for Arnica montana flower heads in 1990, formally validating its traditional external uses. Germany has the strongest phytotherapy tradition regarding arnica and the largest market for arnica-based topical products. The Commission E monograph represents the gold standard regulatory endorsement for arnica's therapeutic applications and explicitly restricts use to external application."
[1]
Homeopathic tradition (established by Samuel Hahnemann, 18th-19th century)
- Arnica montana is one of the most prescribed and well-known homeopathic remedies worldwide
- Homeopathic Arnica (potencies 6C, 12C, 30C, 200C) used for: physical trauma of any kind, bruising, surgical recovery, dental procedures, and childbirth recovery
- Emotional and physical shock following injury or surgery
- Muscle soreness and overexertion
- Pre- and post-operative support -- widely recommended by integrative surgeons and dentists
- Falls and blunt trauma in children (homeopathic pellets are safe for pediatric use)
"Arnica montana was one of the earliest remedies proved (tested) by Samuel Hahnemann, the founder of homeopathy, in the late 18th century. It has since become arguably the single most iconic and widely used remedy in the entire homeopathic pharmacopoeia. Homeopathic Arnica is used in highly diluted form (typically 30C or 200C, which contain no measurable molecules of the original substance) based on the principle of 'like cures like' -- the symptoms that concentrated arnica causes (bruising, sore feeling, shock) are the symptoms that ultra-diluted arnica is said to treat. Clinical trial evidence for homeopathic Arnica is mixed: some studies (particularly in surgical recovery) show modest benefits, while systematic reviews have generally been inconclusive or negative. The distinction between herbal arnica (pharmacologically active, topical only, containing measurable helenalin) and homeopathic arnica (ultra-diluted, taken orally, containing no detectable active compounds) is CRITICAL and must not be conflated."
Native American medicine (related Arnica species)
- Arnica cordifolia, A. fulgens, A. sororia, and other North American Arnica species were used by various indigenous peoples
- Blackfoot nation: poultice of A. fulgens and A. sororia applied to bruises, sprains, and back pain
- Catawba and other Southeast nations: related Asteraceae used similarly for pain and swelling
- Cheyenne: A. cordifolia used externally for sore muscles and joints
- Various tribes used arnica species in sweat lodge preparations and as a wash for sore limbs
"While Arnica montana is exclusively European, several closely related North American Arnica species were used by indigenous peoples for remarkably similar applications -- topical treatment of bruises, sprains, sore muscles, and back pain. This parallel development of similar therapeutic uses for related species across two continents, independently, is notable evidence for the genuine bioactivity of the genus. Native American uses were exclusively external, mirroring the European tradition's ultimate recognition that arnica is for topical application only."
[4]
Eclectic medicine (American, 19th-early 20th century)
- External application for bruises, sprains, and contusions (primary indication)
- Dilute tincture internally in very small doses (0.5-3 drops) for nervous shock, concussion, and prostration following injury -- this internal use is NO LONGER recommended and is considered dangerous
- Specific for 'bruised, sore feeling' -- King's American Dispensatory considered arnica specific for trauma
- External application for chronic joint and muscle pain
- Liniment for sore, stiff muscles after overexertion
"The Eclectic physicians of 19th-century America adopted arnica from European practice. King's American Dispensatory (1898) described it as 'a remedy of great value in injuries attended with stupor... sprains, bruises, contusions, and lacerations.' The Eclectics sometimes used extremely small doses internally for nervous shock, but even they noted the risks of gastric irritation. Felter and Lloyd's King's American Dispensatory emphasized that 'arnica is one of those remedies whose chief value is for external application.' Modern practice has abandoned all internal herbal use."
Modern Research
Arnica gel versus ibuprofen gel for hand osteoarthritis (landmark RCT)
Randomized, double-blind, non-inferiority trial comparing topical arnica gel (A. montana fresh plant 50 g/100 g) with ibuprofen 5% gel in 204 patients with radiologically confirmed osteoarthritis of the finger joints over 3 weeks. Primary outcomes: pain (VAS), hand function (HAQ-DI), grip strength.
Findings: Arnica gel was non-inferior to ibuprofen gel for all primary endpoints. Both treatments significantly reduced pain (arnica: -40.4 mm VAS change; ibuprofen: -39.0 mm VAS change; difference not significant, P=0.45). Hand function improved significantly in both groups. Grip strength increased comparably. Patient satisfaction was similar. Adverse events were comparable between groups (mainly mild local skin reactions). This is the highest-quality clinical evidence for arnica's efficacy, demonstrating that a topical botanical preparation can match the gold-standard topical NSAID for a common chronic pain condition.
Limitations: Single-center study (Switzerland). 3-week duration -- long-term efficacy and safety not assessed. Specific commercial arnica gel product tested; results may not generalize to all arnica preparations. Non-inferiority design; cannot claim superiority. Active comparator only (no placebo arm), making it difficult to separate treatment effect from natural history and placebo response.
[7]
Arnica gel for knee osteoarthritis
Open, multicenter study evaluating arnica gel (A. montana fresh plant tincture) in 79 patients with mild-to-moderate osteoarthritis of the knee over 3-4 weeks. Outcomes: pain (VAS), joint stiffness, functional impairment.
Findings: Significant improvements were observed in pain, stiffness, and function after 3-4 weeks of treatment with topical arnica gel. Pain VAS decreased by approximately 50% from baseline. Joint stiffness and functional limitation also improved significantly. The arnica gel was well tolerated with only minor local skin reactions reported. Results support arnica's efficacy for osteoarthritic pain, complementing the Widrig et al. (2007) hand OA trial.
Limitations: Open-label design without placebo control or active comparator. No blinding. Moderate sample size. Short duration. Natural history of OA symptoms (waxing and waning) could account for some improvement. Nevertheless, the magnitude of pain reduction was clinically meaningful.
[8]
Mechanism of action: Helenalin as an NF-kB inhibitor
In vitro investigation of the molecular mechanism by which helenalin (the primary sesquiterpene lactone of Arnica montana) inhibits NF-kB transcriptional activity. Used Jurkat T-cells and HeLa cells stimulated with TNF-alpha and PMA.
Findings: Helenalin selectively inhibited NF-kB-dependent transcription without affecting AP-1 or NF-AT-dependent transcription. The mechanism was identified as direct alkylation of the p65 (RelA) subunit of NF-kB at Cys38 via Michael addition, preventing DNA binding. Helenalin did not inhibit IkB-alpha degradation or nuclear translocation of NF-kB -- instead, it targets the DNA-binding step specifically. IC50 for NF-kB inhibition was approximately 5 microM. This direct, covalent modification of NF-kB is distinct from corticosteroid or NSAID mechanisms and represents a unique anti-inflammatory pharmacology. The study also demonstrated that the alpha-methylene-gamma-butyrolactone moiety is essential for this activity -- 11,13-dihydrohelenalin (lacking this moiety) was significantly less active.
Limitations: In vitro study; concentrations used may not reflect tissue concentrations achieved by topical application. Cellular toxicity limits the therapeutic window. However, this is the definitive mechanistic study for helenalin's anti-inflammatory action and has been widely cited and confirmed.
[10]
Helenalin structure-activity relationships and anti-inflammatory selectivity
Investigation of helenalin and related sesquiterpene lactones from Arnica montana for their selective inhibition of the transcription factor NF-kB. Compared helenalin, 11alpha,13-dihydrohelenalin, and their esters for NF-kB inhibitory potency and relationship to structural features.
Findings: Helenalin and its esters were confirmed as potent, selective inhibitors of NF-kB transcription factor. The alpha-methylene-gamma-butyrolactone (exocyclic methylene) was identified as a critical pharmacophore for maximal NF-kB inhibition. 11alpha,13-dihydrohelenalin esters (which lack this moiety) showed reduced but still measurable NF-kB inhibitory activity via the remaining cyclopentenone electrophilic center. The selectivity for NF-kB over other transcription factors (AP-1, NFAT, Oct-1) was confirmed. This selectivity profile explains why arnica has potent anti-inflammatory activity with a different side-effect profile than broad-spectrum immunosuppressants.
Limitations: In vitro study. Structure-activity relationships defined in cell-free and cell-based assays may not precisely reflect in vivo pharmacology. Topical bioavailability and metabolism of sesquiterpene lactones in human skin are not fully characterized.
[11]
Review of topical arnica for pain, inflammation, and wound healing
Comprehensive narrative review of the pharmacological evidence and clinical trials for topical arnica preparations in the management of pain, inflammation, and tissue healing. Covers mechanism of action, pharmacokinetics, clinical studies, and safety.
Findings: Reviewed evidence supports arnica's topical anti-inflammatory and analgesic effects mediated primarily by sesquiterpene lactones (helenalin esters) via NF-kB inhibition. Triterpene diols (arnidiol, faradiol) contribute complementary anti-edema effects. Clinical evidence supports efficacy in bruising, sprains, and osteoarthritis. The review emphasized the importance of preparation quality and standardization (sesquiterpene lactone content) for reliable clinical outcomes. Safety profile for topical use is favorable with contact dermatitis as the primary risk.
Limitations: Narrative review; not a formal systematic review. Heterogeneity of arnica preparations across studies complicates comparison. Quality of some older clinical studies is limited by modern standards.
[9]
Systematic review of Arnica montana for post-surgical and post-procedural outcomes
Systematic review evaluating the evidence for Arnica montana (herbal and homeopathic preparations) in reducing post-surgical and post-procedural bruising, swelling, and pain. Included RCTs and controlled studies across various surgical procedures.
Findings: Evidence was mixed across studies. Studies using topical herbal arnica preparations generally showed positive trends for reducing ecchymosis (bruising) following surgical and dermatological procedures. Evidence for homeopathic arnica was less consistent. The review concluded that topical arnica shows promise for reducing post-procedural bruising, with the strongest evidence in facial procedures (rhinoplasty, face-lift) and dermatological treatments (laser procedures). Methodological quality of available studies varied. More standardized, large-scale trials were recommended.
Limitations: Heterogeneity of interventions (herbal vs homeopathic, different concentrations and formulations). Small sample sizes in many individual studies. Variable outcome measures across studies. Mixing of herbal and homeopathic evidence obscures interpretation. Publication bias possible.
Sesquiterpene lactone content and quality assessment of commercial arnica products
Analytical chemistry study examining the sesquiterpene lactone content and profile of commercial arnica products and raw materials to assess quality and consistency.
Findings: Significant variability was found in sesquiterpene lactone content among commercial arnica products. Some products met European Pharmacopoeia standards (minimum 0.4% sesquiterpene lactones for A. montana), while others fell short. Products derived from A. chamissonis showed different lactone profiles (higher dihydrohelenalin:helenalin ratio) compared to A. montana-derived products. The study emphasized the need for rigorous quality control and standardization in the arnica market, as product efficacy is directly linked to sesquiterpene lactone content and profile.
Limitations: Survey of available products at one point in time; market composition changes. Analytical methods and sensitivity may vary. The clinical significance of helenalin vs dihydrohelenalin ratios (A. montana vs A. chamissonis) has not been fully resolved in comparative clinical trials.
[2]
Conservation genetics and population decline of Arnica montana in Europe
Population genetics and conservation biology studies documenting the decline of wild Arnica montana populations across Europe and the genetic consequences of habitat fragmentation.
Findings: Wild Arnica montana populations have declined by 50-90% across much of their European range over the past century. Primary drivers include agricultural intensification (meadow fertilization), abandonment of traditional extensive management practices, and habitat loss. Remaining populations show reduced genetic diversity due to fragmentation and isolation. Small, isolated populations are at increased risk of local extinction due to inbreeding depression, loss of pollinators, and stochastic events. Conservation strategies include restoration of extensively managed meadows, ex situ seed banking, and habitat management agreements. The conservation crisis has accelerated the shift toward cultivated A. chamissonis as the primary commercial source.
Limitations: Conservation data varies by country and region. Population trend estimates are based on available monitoring data which may be incomplete. Genetic studies have focused on specific regional populations and may not represent the full range.
[2]
Preparations & Dosage
tincture (for external use)
Strength: 1:5, 50-70% ethanol (dried flower heads). Commission E and EMA specify this range for the tincture used in external preparations.
Prepare from dried Arnica montana flower heads. Standard maceration: 1:5 ratio in 50-70% ethanol. Macerate dried flowers in the ethanol-water mixture for 10-14 days with regular agitation. Press, filter, and store in dark glass bottles. For external use ONLY: dilute tincture before application -- 1 part tincture to 3-10 parts water for compresses and washes. For mouth rinse: dilute 1:10 in water (approximately 10 mL tincture in 100 mL warm water). DO NOT SWALLOW.
EXTERNAL USE ONLY. Compress: dilute tincture 1:3 to 1:10 with water; apply as a compress to affected area 2-3 times daily. Mouth rinse: 10 mL tincture in 100 mL warm water; gargle and spit, do not swallow.
2-3 times daily for topical application. Mouth rinse: 2-3 times daily after meals.
Acute injuries: 1-2 weeks or until bruising/swelling resolves. Chronic conditions: can be used intermittently long-term for external application. Discontinue if contact dermatitis develops.
External use in children: use more dilute preparations (1:10 dilution). Avoid application to face in young children. Not for internal use at any age.
Arnica tincture is the MOST common preparation form and the basis for most commercial topical products. It is EXCLUSIVELY for external use. The tincture must always be diluted before skin application -- undiluted tincture can cause skin irritation even in non-sensitized individuals. For compresses: soak a clean cloth in the diluted tincture and apply to the affected area for 15-30 minutes. European Pharmacopoeia specifies Arnicae tinctura as the standard preparation. Fresh plant tinctures (1:2 in 50% ethanol, from freshly harvested flowers) are also widely used, particularly in homeopathic mother tincture preparations and some commercial gels (e.g., the preparation used in the Widrig 2007 trial).
infused oil
Strength: Approximately 1:5 (dried flowers to oil by weight). The oil extract primarily captures lipophilic constituents: triterpene diols (arnidiol, faradiol), essential oil components (thymol), carotenoids, and partially the sesquiterpene lactones.
Fill a clean glass jar loosely with dried arnica flower heads (or use a 1:5 ratio by weight). Cover completely with a carrier oil (olive oil, sunflower oil, or sweet almond oil). Ensure all plant material is submerged with at least 2 cm of oil above the flowers. Close the jar and place in a warm location (sunny windowsill or warm cupboard, approximately 35-40 degrees C) for 2-4 weeks, agitating daily. Alternatively, use a gentle heat method: warm the oil and flowers in a double boiler at 40-50 degrees C for 4-8 hours. Strain through fine muslin or cheesecloth, pressing to extract all oil. Store in dark glass bottles in a cool location.
Apply arnica-infused oil to the affected area 2-3 times daily. Massage gently into the skin over bruises, sore muscles, stiff joints, or sprains. Use only on intact, unbroken skin.
2-3 times daily as needed
As needed for acute conditions. Can be used intermittently long-term.
External use only. Suitable for children over 2 years for bruises and bumps. Apply sparingly.
Arnica-infused oil is one of the most traditional and widely used preparations in European folk herbalism. It is particularly suited for massage applications and for making ointments and salves (by combining with beeswax). The oil extraction preferentially captures lipophilic constituents (triterpene diols, essential oil, carotenoids) which contribute significantly to anti-inflammatory and vulnerary activity. The golden-orange color of the finished oil indicates successful extraction of carotenoid pigments. Arnica oil is NOT the same as arnica essential oil (which is rarely produced due to low essential oil content and is extremely concentrated). IMPORTANT: Arnica-infused oil is for EXTERNAL use only on intact skin.
gel
Strength: Variable by product. Clinical trial formulation: fresh plant 50 g/100 g gel (Widrig 2007). Typical commercial products: 10-25% tincture in gel base.
Commercial arnica gels are the most widely available and clinically tested preparation form. Typically formulated with arnica tincture (fresh or dried plant) or arnica extract incorporated into a gel base (commonly carbomer/carbopol gel). The Widrig et al. (2007) trial used a gel containing A. montana fresh plant 50 g/100 g gel. Typical commercial concentrations contain 10-25% arnica tincture in a gel base. Home preparation: incorporate 10-20% arnica tincture (1:5) into a commercially available gel base (aloe vera gel or carbomer gel) by thorough mixing.
Apply a thin layer of arnica gel to the affected area 2-3 times daily. Rub in gently until absorbed. Do not apply to broken skin, open wounds, or mucous membranes.
2-3 times daily
Acute injuries: continue until bruising/swelling resolves (typically 1-2 weeks). Osteoarthritis: can be used long-term with periodic reassessment.
External use in children over 2 years. Apply sparingly to bruises and bumps. Avoid contact with eyes, mouth, and broken skin.
Gel is the preferred preparation form for clinical use and has the strongest evidence base (Widrig 2007 RCT, Knuesel 2002 study). The gel base provides a non-greasy, fast-absorbing vehicle that is practical for application over joints and muscles. Gels facilitate rapid delivery of active constituents to the target tissue. Commercial products vary significantly in quality and concentration -- choose products from reputable manufacturers that specify the tincture concentration or standardized extract content. Look for products listing sesquiterpene lactone content or standardized to helenalin/helenalin ester content.
cream-or-ointment
Strength: Cream: 10-20% tincture or equivalent extract in cream base. Ointment: typically containing 15-25% arnica infused oil in a beeswax-oil base.
Arnica cream: incorporate 10-20% arnica tincture or 5-15% arnica infused oil into a suitable cream base (water-in-oil or oil-in-water emulsion). Arnica ointment: melt beeswax (1 part) with arnica-infused oil (4-5 parts) at 60-65 degrees C, stir continuously while cooling until the ointment sets. Common ointment recipe: 200 mL arnica-infused oil + 25-30 g beeswax. For commercial standardized products: follow manufacturer formulation specifications using standardized arnica extract.
Apply to affected area 2-3 times daily. Rub in gently. Use only on intact, unbroken skin.
2-3 times daily
As needed for acute conditions; can be used intermittently for chronic conditions.
External use in children over 2 years. Apply sparingly.
Creams and ointments provide more sustained contact with the skin compared to gels and are preferred for dry skin conditions or when a moisturizing effect is desired. Ointments (oil-based, no water) have the advantage of extended shelf life and greater occlusion, which enhances penetration of lipophilic constituents. Commission E and EMA recognize creams and ointments as appropriate external preparation forms. Traditional European pharmacies (Apotheken) have compounded arnica ointments for centuries.
compress-or-poultice
Strength: Tincture compress: 1 part tincture to 3-10 parts water. Infusion compress: 2 tablespoons dried flowers per 150-200 mL water.
Compress: Dilute arnica tincture (1:3 to 1:10 with water). Soak a clean cloth or gauze pad in the diluted tincture. Apply to the affected area and leave in place for 15-30 minutes. Can be covered with plastic wrap to prevent evaporation and maintain moisture. Poultice (traditional): Steep 2 tablespoons of dried arnica flowers in 150-200 mL of just-boiled water for 10 minutes. Strain. Soak a cloth in the warm infusion and apply to the affected area. Alternatively, the warm strained flowers themselves can be placed in a muslin bag and applied directly.
Apply compress 2-3 times daily for 15-30 minutes per application. Ensure skin is intact and unbroken.
2-3 times daily
Acute injuries: daily application for 3-10 days until swelling and bruising resolve.
Use more dilute preparation (1:10 tincture dilution) for children. Shorter application time (10-15 minutes).
The compress is one of the oldest and most traditional preparation methods for arnica. It is the preparation form most directly described in Commission E for acute injuries. Compresses allow direct, sustained contact of the active preparation with the affected area and can be applied at varying temperatures (cool compresses for acute swelling, warm compresses for chronic stiffness). The dilution of the tincture is important -- undiluted tincture on the skin can cause irritation even in non-allergic individuals. For cold compresses: chill the diluted tincture solution in the refrigerator before soaking the cloth.
homeopathic preparations
Strength: Potencies: 6C, 12C, 30C, 200C (centesimal dilutions). Mother tincture (phi): 1:2 fresh plant in ethanol.
Homeopathic Arnica montana is prepared by serial dilution and succussion (vigorous shaking) according to the Homeopathic Pharmacopoeia. The mother tincture (phi) is prepared from the whole fresh flowering plant. Serial dilutions: 1C = 1:100 dilution; 6C = six serial 1:100 dilutions; 30C = thirty serial 1:100 dilutions (far beyond Avogadro's number, containing no measurable molecules of the original substance). Available as sugar pellets (globules), tablets, or liquid drops. The most commonly used potencies are 6C, 12C, 30C, and 200C.
Homeopathic Arnica 30C: 3-5 pellets dissolved under the tongue, 3 times daily for acute conditions. 200C: single dose for acute trauma. Follow homeopathic prescribing guidelines or practitioner recommendation. These preparations are considered safe for oral use as they contain no pharmacologically active concentration of helenalin.
Acute: every 2-4 hours initially, reducing to 3 times daily as symptoms improve. Chronic: 1-2 times daily.
Acute conditions: 3-7 days. Pre/post-surgical: begin 1-2 days before surgery, continue 5-7 days after.
Homeopathic Arnica is considered safe for children of all ages. 30C: 3 pellets dissolved under the tongue. Very widely used by parents for children's bumps, falls, and bruises.
CRITICAL DISTINCTION: Homeopathic Arnica preparations are pharmacologically distinct from herbal arnica preparations. At potencies of 12C and above, no measurable molecules of helenalin or other active plant compounds remain. Homeopathic Arnica is safe for oral use precisely because it is ultra-dilute. It operates (if it operates) through a mechanism entirely different from the pharmacological actions of helenalin -- the mechanism claimed by homeopathy (water memory, nanopharmacology) is not accepted by mainstream pharmacology. Nevertheless, homeopathic Arnica is extremely widely used worldwide and has been the subject of numerous clinical trials, with mixed results. Several systematic reviews have been published; Ernst & Pittler (1998) found limited evidence, while some individual trials (particularly in surgical recovery) have reported positive results. Regardless of one's position on homeopathic theory, the safety of these ultra-dilute preparations for oral use is not in question.
Safety & Interactions
Class 2c
Not to be used with specific medications (AHPA Botanical Safety Handbook)
Contraindications
ABSOLUTE CONTRAINDICATION: Arnica montana herbal preparations (tincture, tea, decoction, extract containing pharmacologically active concentrations of helenalin) must NEVER be taken internally by any route. Helenalin is a potent cytotoxin that causes: severe gastroenteritis with bloody vomiting and diarrhea; tachycardia and cardiac arrhythmias; severe hepatotoxicity; nephrotoxicity; skeletal muscle weakness and paralysis; central nervous system depression; and death in severe cases. The estimated lethal dose in humans is approximately 70 g of dried flower heads or equivalent. Even sub-lethal internal doses can cause significant multi-organ damage. This is the MOST IMPORTANT safety concern for arnica and must be emphasized to all patients and practitioners. The sole exception to internal use is homeopathic preparations (6C and above) which contain no pharmacologically active concentrations of helenalin.
Arnica preparations must NOT be applied to open wounds, cuts, abrasions, ulcers, surgical incisions, or any area where the skin barrier is compromised. Sesquiterpene lactones (helenalin) applied to broken skin can cause severe local irritation, delayed wound healing, and potentially allow systemic absorption of toxic compounds. The AHPA classification '2c' specifically indicates 'not for use on open or damaged skin.' Commission E and EMA both restrict arnica to application on intact skin only. If the skin over a bruise or sprain is cut or abraded, arnica should not be applied until the skin has fully healed.
Patients with confirmed allergy to plants of the Asteraceae (Compositae) family (including ragweed, chrysanthemums, marigolds, daisies, chamomile) should not use arnica topically. Sesquiterpene lactones (particularly helenalin and its esters) are potent allergenic sensitizers -- they are among the most common causes of plant-related allergic contact dermatitis in Europe. Cross-reactivity between Asteraceae species is well-documented. Individuals with known Compositae sensitivity are at high risk of developing allergic contact dermatitis from arnica application.
Extended or repeated application of arnica preparations over large body surface areas should be avoided to minimize the risk of contact sensitization and systemic absorption. Continuous daily application to the same skin area for longer than 2 weeks without reassessment is not recommended. Large-area application increases the total dose of sesquiterpene lactones absorbed transdermally and the risk of developing allergic sensitization.
Drug Interactions
| Drug / Class | Severity | Mechanism |
|---|---|---|
| Warfarin, heparin, and other anticoagulants (Anticoagulants) | theoretical | Helenalin and related sesquiterpene lactones may have mild antiplatelet activity. Topical application over large areas or on thin-skinned areas could theoretically lead to sufficient systemic absorption to potentiate anticoagulant effects. Additionally, arnica's tissue-level circulatory stimulant action could theoretically increase bleeding from subcutaneous capillaries in anticoagulated patients. |
| Aspirin and other antiplatelet agents (Antiplatelet agents) | theoretical | Theoretical additive antiplatelet effect if sufficient systemic absorption occurs from topical application. Similar mechanism to anticoagulant interaction above. |
| Antihypertensive medications (Antihypertensives) | theoretical | Internal use of arnica (WHICH IS CONTRAINDICATED) could potentially affect blood pressure through cardioactive effects of helenalin. This interaction is theoretical and relevant only in the context of accidental or intentional internal ingestion, not normal topical use. |
Pregnancy & Lactation
Pregnancy
unsafe
Lactation
insufficient data
Topical arnica during pregnancy: The AHPA classifies arnica as '2b' (not to be used during pregnancy). While normal topical use on small areas of intact skin is unlikely to result in significant systemic absorption, arnica has been historically associated with uterine stimulant activity when taken internally. As a precautionary measure, topical arnica should be avoided during pregnancy, particularly in the first trimester and near the application area of the abdomen or lower back. If used topically during pregnancy (e.g., for a specific bruise), application should be limited, brief, and away from the abdomen. INTERNAL USE IS ABSOLUTELY CONTRAINDICATED in pregnancy -- helenalin is a potent toxin that could cause severe fetal harm. Homeopathic arnica (30C+) is widely used during labor and postpartum in some traditions, as it contains no pharmacologically active compounds, though definitive safety data from controlled studies is lacking. Lactation: Insufficient data on excretion of arnica compounds into breast milk from topical application. Avoid application to the breast or nipple area to prevent infant ingestion. General topical use on other body areas is likely low-risk but not formally studied during breastfeeding.
Adverse Effects
References
Monograph Sources
- [1] German Federal Institute for Drugs and Medical Devices (BfArM), Commission E. Commission E Monograph: Arnicae flos (Arnica Flower). Bundesanzeiger (Federal Gazette), Germany. Published in English: Blumenthal M, et al. (eds). The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. American Botanical Council, Austin, TX (1990)
- [2] European Medicines Agency (EMA), Committee on Herbal Medicinal Products (HMPC). European Union Herbal Monograph on Arnica montana L., flos. EMA/HMPC/198793/2012. European Medicines Agency, London (2014)
- [3] World Health Organization. WHO Monographs on Selected Medicinal Plants, Volume 2: Flos Arnicae. World Health Organization, Geneva (2002)
- [4] Hoffmann D. Medical Herbalism: The Science and Practice of Herbal Medicine. Healing Arts Press, Rochester, VT (2003)
- [5] Mills S, Bone K. Principles and Practice of Phytotherapy: Modern Herbal Medicine (2nd edition). Churchill Livingstone/Elsevier, Edinburgh (2013)
- [6] Gardner Z, McGuffin M (eds). AHPA Botanical Safety Handbook (2nd edition). American Herbal Products Association, CRC Press, Boca Raton, FL (2013)
Clinical Studies
- [7] Widrig R, Suter A, Saller R, Melzer J. Choosing between NSAID and arnica for topical treatment of hand osteoarthritis in a randomised, double-blind study. Rheumatol Int (2007) ; 27 : 585-591 . DOI: 10.1007/s00296-007-0304-y . PMID: 17309376
- [8] Knuesel O, Weber M, Suter A. Arnica montana gel in osteoarthritis of the knee: an open, multicenter clinical trial. Adv Ther (2002) ; 19 : 209-218 . DOI: 10.1007/BF02850361 . PMID: 12539881
- [9] Iannitti T, Morales-Medina JC, Bellavite P, Rottigni V, Palmieri B. Effectiveness and safety of Arnica montana in post-surgical setting, pain and inflammation. Am J Ther (2016) ; 23 : e184-e197 . DOI: 10.1097/MJT.0000000000000036 . PMID: 24368435
- [10] Lyss G, Knorre A, Schmidt TJ, Pahl HL, Merfort I. The anti-inflammatory sesquiterpene lactone helenalin inhibits the transcription factor NF-kappaB by directly targeting p65. J Biol Chem (1997) ; 272 : 11446-11454 . DOI: 10.1074/jbc.272.17.11446 . PMID: 9111055
- [11] Klaas CA, Wagner G, Laufer S, Sosa S, Della Loggia R, Bomme U, Pahl HL, Merfort I. Studies on the anti-inflammatory activity of phytopharmaceuticals prepared from Arnica flowers. Planta Med (2002) ; 68 : 385-391 . DOI: 10.1055/s-2002-32067 . PMID: 12058311
Pharmacopeias & Reviews
- [12] European Pharmacopoeia Commission. European Pharmacopoeia Monograph: Arnicae flos (01/2008:1391) and Arnicae tinctura (01/2013:1809). European Directorate for the Quality of Medicines & HealthCare (EDQM), Council of Europe, Strasbourg (2013)
- [13] British Herbal Medicine Association. British Herbal Pharmacopoeia (BHP): Arnica montana flower. British Herbal Medicine Association, Bournemouth (1996)
Last updated: 2026-03-02 | Status: review
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