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Botanical Description & Habitat

Arnica montana


Common Names

Arnica flowersArnica root
Common arnicaLeopards bane
Mountain arnicaMountain tobacco

Europe, Russia, Siberia, Canada, and north-western United States; mountain areas and moist upland meadows.

A perennial plant whose brown rootstock produces a slightly hairy, branched stem; the stem can reach 1-2 feet in height. Arnica grows 1-3 pairs of oblong, ovate basal leaves. The upper stem leaves are smaller and sessile; all leaves are bright green and pubescent on the upper surface. The stem terminates by branching into 1-3 peduncles, each bearing a flower which is present from June to August. The flowers are bright yellow and daisy-like, with strongly-scented foliage.

Medicinal Parts
Flower heads - dried

Historical Properties & Uses

Arnica is popular abroad for its versatility as a diaphoretic, diuretic, emollient, expectorant, stimulant, vasodilator, and vulnerary. In Germany, for example, arnica is one of the most prescribed herbal remedies for stimulating the immune system. It is seldom used in North America, and indeed has acquired a somewhat unfavorable reputation in the United States, perhaps due to lack of knowledge about its use.

Arnica is used in very dilute solutions: externally, as a salve, tincture or compress to promote healing of wounds, bruises, and irritations; and internally, as an expectorant or as a gargle to soothe inflammations of the throat and mouth. Arnica is also a common homeopathic remedy for multiple sclerosis.

Arnica's main alkaloids resemble the active alkaloids of echinacea, both in structure and in activity.

Method of Action

Arnica Has Cardiovascular Action
Arnica has been found to strengthen circulation by stimulating coronary heart vessels and by increasing heart capacity. There is such a thing as too much of a good thing, however, and too much arnica extract could produce hypertension and adverse effects on the heart.

Arnica Is An Immunostimulant
In support of the immunostimulant property referred to above, it has been found arnica extract stimulates phagocytosis in laboratory animals. Among the bacteria counteracted were Listeria monocytogenes and Salmonella typhimurium.

Drug Interactions & Precautions

Known Interactions

Arnica has coumarin constituents and therefore acts as an anticoagulant.

As arnica's diuretic action increases the renal excretion of sodium and chloride, the herb may potentiate the hyperglycemic and hyperuricemic effects of glucose-elevating agents.

Diuretics in general may potentiate the action of antihypertensive, ganglionic or peripheral adrenergic blocking drugs, tubocurarine and, to a lesser degree, norepinephrine. It should also be noted the effects of dopamine and diuretic agents are additive.

Possible Interactions
The sympathomimetic action of the uterine relaxant ritodrine HCl and the vasoconstricting property of arnica are additive.

In conjunction with corticotropin (ACTH) or corticosteroids, this diuretic herb is more prone to produce hypokalemia. The use of diuretics in general may require dosage adjustments of antidiabetic drugs. The diuretic action of the herb may reduce renal clearance of lithium. An initial dose of the antihypertensive captopril may cause a severe drop in blood pressure within three hours if a strong diuretic such as arnica is also being used.

The pressor effect of this sympathomimetic agent may be markedly potentiated by monoamine oxidase inhibitors (MAOI's) and tricyclic antidepressants. The use of this herb in obstetrics (i.e., to correct hypotension) in conjunction with oxytocic drugs may produce hypertension. Additive pressor effects may occur when using arnica with the analeptic doxapram HCl.

Concurrent administration of large amounts of this herb and procarbazine antineoplastic drugs may induce a sudden hypertensive crisis.

Colchicine may increase sensitivity, or enhance the response, to arnica.

The cholinergic action of arnica may be antagonized by antihistamines, anticholinergics (atropine), nitrites, nitrates, pentaerythritol tetranitrate, and tetraethylammonium chloride. The cholinergic action of arnica may potentiate depolarizing muscle relaxants such as decamethonium; if the interaction is severe, respiratory paralysis may result.

The anti-inflammatory activity of arnica can be seriously inhibited by phenobarbital and certain other sedatives and hypnotics, such as chloral hydrate and meprobamate. This is also true of beta-adrenergic blocking agents, such as propranolol.

Due to the presence of blood serum platelet aggregation inhibitors (e.g. linolenic acid), arnica may potentiate the effects of anticoagulant drugs such as heparin.

The strong diuretic action of arnica may produce digitalis toxicity if digitalis glycosides are being used. In conjunction with aminoglycoside antibiotics, it may also produce ototoxicity; combined with ethyl alcohol, barbiturates, or narcotics, it may produce orthostatic hypotension.

Strong diuretics such as arnica, in conjunction with indomethacin, may produce natriuretic effects. The herb may also enhance the nephrotoxicity of cephaloridine.

Prolonged use of this diuretic may affect certain laboratory test results such as electrolytes, especially potassium and sodium, blood urea nitrogen (BUN), uric acid, glucose, and protein bound iodine (PBI).

Safety Factors & Toxicity

Arnica should be used in only very dilute solutions, even externally, as it can blister, irritate and inflame the skin. Most herbalists insist this herb only be used under medical supervision.

It is regarded as unsafe by the FDA on the grounds it contains substances affecting the heart and vascular systems, and it can produce violent toxic gastroenteritis, nervous disturbances, a change in pulse rate, intense muscular weakness, collapse and death.

Arnica has been known to cause contact dermatitis in sensitive individuals.

This herb has approval status by the German Commission E as an analgesic.


Blumenthal, M (Ed.): The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. American Botanical Council. Austin, TX. 1998.

Preparation & Administration

Tincture of flowerheads
1:10 in 45% alcohol

Caution: This tincture is for external application only. Discontine use if there is an allergic reaction.

This herb has approval status by the German Commission E as a topical anti-inflammatory.

Daily dosages are as follows:

2 g herb per 100 ml of water
Arnica ointment: not more than 20 - 25% tincture or 15% Arnica oil
Arnica oil: 1 part herb: 5 parts fatty oil


Blumenthal, M (Ed.): The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. American Botanical Council. Austin, TX. 1998.

Note: This Herbal Preparation information is a summary of data from books and articles by various authors. It is not intended to replace the advice or attention of health care professionals.


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