The arnica plant is a member of the sunflower family. It has been used medically for centuries. The root of the plant contains chemicals that help with inflammation and joint and tissue health. Arnica is also used in ointments to help with muscle health, pain management, and wound care. Although the medicine from the plant is beneficial for many reasons, the plant can be toxic if eaten in large amounts.
People with known sensitivity to members of the daisy family should not use arnica for medical purposes. Arnica is also not to be used during pregnancy. It should also not be used on eyes, mucous membranes or damaged skin. Sometimes use of arnica may increase your risk of bleeding. Arnica should also not be ingested in large quantities. Arnica can be found in in whole, cut and dried herb form as well as gels, ointment, and oil.
The medicinal parts of Arnica are the ethereal oil of the flowers, the dried flowers, the leaves collected before flowering and dried, the roots, and the dried rhizome and roots.
Flower and Fruit
The terminal composite flower is found in the leaf axils of the upper pair of leaves. They have a diameter of 6 to 8 cm, are usually egg yolk-yellow to orange-yellow, but occasionally light yellow. The receptacle and epicalyx are hairy. The 10 to 20 female ray flowers are linguiform. In addition, there are about 100 disc flowers, which are tubular. The 5-ribbed fruit is black-brown and has a bristly tuft of hair.
Leaves, Stem, and Root
Arnica is an herbaceous plant growing 20 to 50 cm high. The brownish rhizome that is 0.5 cm thick by 10 cm long, usually unbranched, in 3 sections, and sympodial. The rhizome may also be 3-headed with many yellow-brown secondary roots. Leaves are in basal rosettes. They are in 2 to 3 crossed opposite pairs and are obovate and entire-margined with 5 protruding vertical ribs. The glandular-haired stem has 2 to 6 smaller leaves, which are ovate to lanceolate, entire-margined or somewhat dentate.
The flower heads are aromatic; the taste is bitter and irritating.
Arnica is found in Europe from Scandinavia to southern Europe. It is also found in southern Russia and central Asia.
Arnica flower consists of the fresh or dried inflorescence of Arnica montana or Arnica chamissonis. The flower should be dried quickly at 45º to 50ºC.
Not to be Confused With
Other yellow-flowering Asteracea.
Arnica Flowers, Arnica Root, Leopard's Bane, Mountain Tobacco, Wolfsbane
Actions & Pharmacology
Sesquiterpene lactones of the pseudo-guaianolid-type: particularly esters of the helenalin- and 11,13-dihydrohelenalins with short-chained fatty acids such as acetic acid, isobutyric acid, 2- methyl-butyric acid, methylacrylic acid, isovaleric acid or tiglic acid
Volatile oil: with thymol, thymol esters, free fatty acids
Polyynes: including tri-dec-1-en-penta-3,5,7,9 11-in
Caffeic acid derivatives: including chlorogenic acid, 1,5-dicaffeoyl quinic acid
Flavonoids: numerous flavone and flavonol glycosides and their aglycones
Arnica preparations have demonstrated wound-healing, antiseptic, and mild analgesic properties in animal and in vitro studies when applied topically. The flavonoid bonds, essential oils, and polyynes may also be involved. In cases of inflammation, Arnica preparations also show analgesic and antiseptic activity. The sesquiterpenes (helenalin) in the drug have an antimicrobial effect in vitro and an antiphlogistic effect in animal tests. A respiratory-analeptic, uterine tonic and cardiovascular effect (increase of contraction amplitude with simultaneous increase in frequency, i.e., positive inotropic effect) was demonstrated. Further in vitro and in vivo studies of Arnica preparations or isolated ingredients have shown antiaggregatory, immunostimulatory, cytotoxic, cardiotonic, and antioxidative effects. More controlled and comparative studies are necessary to define optimal therapies and to determine Arnica's place in therapy.
The mild analgesic properties of Arnica flowers and its preparations are mainly attributed to the sesquiterpene lactones helenalin and dihydrohelenalin (Wichtl, 1997). Writhe reflex tests in mice demonstrated a marked analgesic action (Fachinformation Arthrosenex AR, 1998).
The anti-inflammatory effect of the sesquiterpene lactone helenalin was found to be due to molecular mechanisms preventing the release of the transcription factor NF-kB (an immune regulator). Helenalin inhibited the release of IkB (an inhibitory subunit) by modification of the NF-kB/IkB complex, resulting in a suppression of the immune regulator NF-kB (Lyss et al, 1997; Schaffner, 1997). Helenalin inhibited the oxidative phosphorylation, chemotaxis, and mobility of human polymorphonuclear neutrophiles. It contributed to a reduction of the size of inflamed areas by stabilizing lysosomal membranes and was thought to possess therapeutic efficacy in the treatment of chronic arthritis. (Fachinformation Arthrosenex AR, 1998).
The wound-healing and antiseptic properties of Arnica flowers and its preparations are mainly attributed to the sesquiterpene lactones helenalin and dihydrohelenalin and related esters, which demonstrated bactericidal (e.g. salmonella) and fungicidal activity (Anon, 1998; Wichtl, 1997).
Polysaccharides containing 65% to 100% galacturonic acid isolated from Arnica flowers caused a modification of the immune system response by inhibition of the complement system and a marked enhancement of phagocytic activity in vivo (Anon, 1998). Compounds of Arnica were found to stimulate macrophages to excrete tumor necrosis factor (Puhlmann et al, 1991).
Gonarthrosis has been treated effectively by intra-articular injections of a combination preparation containing Arnica. Intra-articular injection of a homeopathic combination preparation containing extracts of Arnica montana, Sanguinaria canadensis, Solanum dulcamara, sulfur, and Toxicodendron quercifolium (Zeel comp®) had beneficial effects in the treatment of 446 patients with gonarthrosis. A mean dose of 2 injections per week was administered for a mean length of therapy of 4 to 5 weeks. Pain and joint stiffness improved in 90% of the patients. The combination preparation was tolerated well and had a favorable side effect profile compared to other commonly prescribed medications. No adverse effects have been recorded except for local reversible knee irritations (Anon, 1996).
Several double-blind, randomized, placebo-controlled studies failed to find beneficial effects of homeopathic Arnica preparations in the prevention and treatment of delayed-onset muscle soreness (Vickers et al, 1998; Vickers et al, 1997; Gulick et al, 1996).
Similar results were obtained with homeopathic Arnica 30X therapy of delayed onset muscle soreness in 519 runners in a double-blind, placebo-controlled randomized study. Five pills (either a placebo or Arnica) were taken two times daily starting the evening before the race for 5 days. The level of muscle soreness was determined by a 7-point Likert scale (a list of descriptives for level of muscle soreness). No differences between the Arnica group and the placebo group were found for Leikert scores or race time (Vickers et al, 1998).
Homeopathic therapy was ineffective in the treatment of delayed onset muscle soreness in a double-blind, placebo-controlled, randomized study of 68 volunteers who underwent a 10-minute period of bench stepping carrying a small weight. The patients were treated either with one tablet of a homeopathic complex of Arnica 30C, Rhus toxicodendron (Rhus tox) 30C, sarcolactic acid 30C three times daily, or placebo. Mean muscle soreness was assessed over a 5-day period following the exercise. No significant differences between homeopathic therapy and placebo were found (Vickers et al, 1997).
Neither topical Arnica montana ointment nor sublingual Arnica montana pellets have been effective in abating the signs and symptoms of delayed onset muscle soreness after forearm extensor muscle exercise on a Lido isokinetic dynamometer in a placebo-controlled, randomized study of 70 untrained volunteers. Patients were assigned to various treatment techniques. In the two Arnica groups, patients either received a thin layer (approximately 0.5 g) of 0.4% topical Arnica montana ointment on the posterior forearm every 8 hours or three sublingual Arnica montana pellets 6C every 8 hours for three days. Data on active and passive wrist flexion and extension, forearm girth, limb volume, visual analog pain scale, muscle soreness index, isometric strength, concentric and eccentric wrist total work, concentric and eccentric wrist average peak torque, and concentric and eccentric angle of peak torque were collected in the beginning and at the end of the exercise and 20 minutes, 24, 48 and 72 hours after treatment. No significant differences were found between the therapy regimens and the control group (Gulick et al, 1996).
Combination therapy consisting of Arnica and Rhus tox 30C produced beneficial effects in the treatment of delayed onset muscle soreness in a randomized, double-blind, placebo-controlled study of 50 volunteers undergoing vigorous bench stepping exercise. One tablet of the homeopathic preparation was administered 3 times daily, starting 24 hours before the exercise. The differences, however, between homeopathic therapy and placebo did not reach statistical significance (Jawara, 1997).
Three randomized, placebo-controlled, double-blind clinical trials were carried out sequentially at a single primary care unit specializing in knee surgery to determine the effectiveness of homeopathic Arnica on postoperative swelling and pain following knee surgery of one of the following three types: arthroscopy (ART; n=227), artificial knee joint implantation (AKJ; n=35), or cruciate ligament reconstruction (CLR; n=57). All participants received either placebo or homeopathic Arnica prior to the procedure (1 X 5 globules) of the homeopathic dilution 30x followed by 3 x 5 globules daily. Those randomized to receive the Arnica prior to the procedure showed a trend towards less postoperative swelling compared to patients receiving placebo—although this difference was only significant for the patients randomized to get homeopathic Arnica in the CLR group (Brinkhaus, 2006).
A small but statistically significant decrease in pain score compared to placebo was reported in a randomized trial of homeopathic Arnica for post-tonsillectomy analgesia at a tertiary referral center. The 190 tonsillectomy patients received either Arnica 30c or placebo (2 tablets 6 times in post-operative day followed by 2 tablets twice daily for subsequent 7 days). Questionnaires from 111 patients were available for analysis. A significantly (p<0.05) larger drop in pain score from postoperative day 1 to 14 (28.3) was recorded by the Arnica group compared to the placebo group (pain score 23.8). Variables such as quantity of analgesia and antibiotics used, number of days to return to work and or return to normal swallowing were not significantly different between the treatment to placebo group (Robertson, 2007).
No differences in pain or hand function improvement were detected after 21 days of treatment with either topical gel preparations of ibuprofen 5% or Arnica 50 g tincture/100g, DER 1:20 in a randomized, double-blind study in 204 individuals with confirmed and active osteoarthritis of inter-phalangeal joints of the hands. Adverse event rates were similar, with six patients using ibuprofen and five patients using Arnica reporting problems (Widrig, 2007).
A gel preparation of Arnica flowers applied externally to the limbs of 12 male volunteers was more effective than placebo in the treatment of muscle ache. In a randomized, double-blind, placebo-controlled study, 89 patients with venous insufficiency received Arnica gel (20% tincture) or placebo. It was reported that Arnica treatment produced improvements in venous tone, edema and in feeling of heaviness in the legs. (Barnes et al, 2002).
No significant differences in postoperative pain and infection management between homeopathic therapy with Arnica 30C and placebo were found in a randomized, placebo-controlled, double-blind study of 93 women undergoing total abdominal hysterectomy. Two doses of Arnica 30C or placebo were administered 24 hours before surgery followed by 3 daily doses for 5 days. With homeopathic treatment, 76% of the patients had to take additional antibiotics, compared to 71% in the placebo group; and mean pain scores were 32.6 for Arnica and 31.0 for placebo (Hart et al, 1997).
Homeopathic remedies including Arnica D30 have been ineffective in pain management of 24 patients undergoing oral surgical procedures in a randomized, double-blind, placebo-controlled study. Postoperative pain measured by visual analog scales and postoperative recovery assessed by swelling, bleeding, and the ability to open the mouth was not significantly affected by homeopathic therapy. The treatment regimen consisted of one dose of 3 tablets administered quarterly for the first 3 hours, thereafter 1 dose per hour until bedtime, and 2 doses on the following morning at an interval of 3 hours. Treatment continued with 4 daily doses (Loekken et al, 1995). Homeopathic Arnica preparations had no effect on surgically induced trauma after total abdominal hysterectomy or bilateral oral surgery.
Two clinical studies demonstrated beneficial effects of homeopathic Arnica therapy in the treatment of diabetic retinopathy (Zicari et al, 1998; Zicari, 1997). Homeopathic Arnica 5CH therapy produced statistically significant improvement in retinal sensitivity and functional improvement in the peripheral retinal areas in a double-masked, randomized, placebo-controlled study of 29 insulin-dependent diabetes mellitus patients with diabetic retinopathy. Either 3 pearls of Arnica 5CH per day or placebo were administered three times daily for three months. No significant differences regarding intraocular pressure, ophthalmoscopic appearance, or metabolic condition between the placebo group and the Arnica group were recorded (Zicari et al, 1998; Zicari, 1997).
A statistically significant increase of red critical retinal flicker fusion was found in a study of 30 non-insulin-dependent diabetes mellitus patients after three months of therapy with Arnica 5CH. A daily dose of 3 pearls of Arnica 5CH or placebo was administered. Intraocular pressure and ophthalmoscopic appearance were not affected by Arnica therapy, but the metabolic condition improved during placebo therapy (Zicari, 1995).
Homeopathic Arnica preparations had no effect on surgically induced trauma after total abdominal hysterectomy or bilateral oral surgery (Hart et al, 1997; Loekken et al, 1995).
Indications & Usage
Approved by Commission E:
- Fever and colds
- Inflammation of the skin
- Inflammation of the mouth and pharynx
- Common cold
- Blunt injuries
- Tendency to infection
External folk medicine uses include consequences of injury such as traumatic edema, hematoma, contusions, as well as rheumatic muscle and joint problems. Other applications are inflammation of the oral and throat region, furunculosis, inflammation caused by insect bites and phlebitis. In Russian folk medicine, the drug is used to treat uterine hemorrhaging. Furthermore, the drug is used for myocarditis, arteriosclerosis, angina pectoris, exhaustion, cardiac insufficiency, sprains, and contusions and for hair loss due to psychological causes. While some uses are plausible, most have not been proved.
Arnica is contraindicated in people with a known sensitivity to members of the daisy family, such as chamomile, marigold, or yarrow.
Arnica preparations not to be used during pregnancy.
Precautions & Adverse Reactions
Arnica preparations should not be administered on mucous membranes, eyes, or damaged skin.
Frequent administration, in particular of the undiluted tincture, as well as with contacts with the plant, lead to sensitization. Prolonged topical administration on damaged skin, e.g., in injuries or ulcus cruris (indolent leg ulcers) may cause eczema and edematous dermatitis with the formation of pustules. Arnica preparations may cause cardiac arrhythmia, tremor, dizziness, and collapse when used internally at doses higher than those recommended. Oral administration is considered to be potentially unsafe, and ingestion of parts of the whole plant or of Arnica preparations has been reported to cause gastroenteritis, stomach pain, severe diarrhea, vomiting, cardiac arrest and death.
Anticoagulants, Antiplatelets, Low Molecular Weight Heparins, and Thrombolytic Agents
Concomitant use of Arnica may result in increased risk of bleeding. Clinical Management: Arnica is generally used as a homeopathic or external preparation and may not be ingested in quantities large enough to cause an interaction. Due to limited data, monitor patients taking Arnica with antiplatelet agents for signs and symptoms of excessive bleeding.
Overdoses taken internally can lead to poisonings, characterized by severe mucous membrane irritation (vomiting, diarrhea, mucous membrane hemorrhage) and a brief stimulation of cardiac activity followed by cardiac muscle palsy. For that reason, internal administration of the drug is strongly discouraged. High dose Arnica therapy may cause arrhythmia and tachycardia.
Mode of Administration
Arnica is used in the form of the whole herb, cut herb or herb powder for infusions, extracts, and tinctures; gel, oil, and poultice for external application.
Commercial pharmaceutical preparations include gels, ointments, tinctures, oils, and plasters.
Arnica tincture (3x to 10x dilutions with water) is used to prepare a poultice. A tincture is prepared using 1 part Arnica flowers and 10 parts ethanol 70% v/v (according to DAB 10). Arnica oil is an extract of 1 part herb and 5 parts slightly warmed fatty oil. Ointments are made up with up to 15% Arnica oil or with 10 to 25% tinctures in a neutral ointment base. Mouthwashes are prepared as a tincture in 10x dilution.
Tincture for cataplasm: tincture in 3x to 10x dilution. For mouth rinses: tincture in 10x dilution. Ointments should contain a maximum of 15% Arnica oil.
When stored, the drug should be tightly sealed and protected from light.