Arnica: all you need to know

by Dr Karen Bridgman January 19, 2016

Ancient names of arnica (Arnica montana) are leopard’s bane, wolf bane and mountain tobacco, leading one to wonder what uses this plant was put to originally. There are 32 species of arnica growing in northern temperate regions right up to the Arctic, many of which have similar therapeutic activity. Arnica loves mountainous areas and usually grows in colonies. It flowers in summer. The leaves form a flat rosette, from the centre of which rises a flower stalk, about 20–60cm high, bearing yellow daisy-like flowers. This flower is used today but for external use only. The rhizome has occasionally been used traditionally.

Arnica has an ancient tradition as a remedy in Germany and Austria, mainly for bruising and sprains. It has also been used traditionally for heart complaints — in old age, Goethe (1749–1832) was recorded taking arnica tea for angina. Today, the tea is not recommended to be taken internally. However, in Europe it is often used (in low doses) as a natural source of food flavouring, although this is banned in the US and considered unsafe, apart from in alcoholic beverages.

Due to its once vast availability, arnica’s flower was previously used for a variety of purposes, including for antibacterial, antifungal, anti-inflammatory, analgesic and anti-neuralgic effects.

Active ingredients

Arnica contains more than 150 active components, including alkaloids, amines, carbohydrates (including polysaccharides and inulin), coumarins, flavonoids (the yellow pigments in the flower with anti-inflammatory properties) and sesquiterpenes of the helenalin type, as well as volatile oil components.

Arnica is prepared homœopathically for both internal and external use, but is prepared herbally in ointments, creams, gels and compresses. Today, it is not used internally as a herbal preparation but is very effective topically.

Uses

As arnica is potentially toxic if taken internally other than as a homœopathic, today it is used topically and has excellent counter-irritant properties, making it invaluable for sprains and strains particularly, but also for unbroken chilblains, alopecia and rheumatoid complaints.

Commission E has approved its use for injuries and accidents: bruising, dislocation, oedema from injury (swelling) and rheumatic muscle and joint problems. It has also been approved for inflammation of the oral and throat region.

Contemporary studies demonstrate in-vitro antimicrobial, anti-inflammatory, positive inotropic effects, respiratory stimulating and uterine activities.

Arnica was found to be as effective as NSAIDs (non-steroidal anti-inflammatory drugs such as aspirin, voltaren etc) in improving pain and hand function in hand osteoarthritis.

Arnica is also used by patients undergoing surgery to reduce post-operative pain, bruising and swelling and promote recovery.

Arnica in action

Anti-inflammatory activity

The main anti-inflammatory component of arnica (working at multiple sites) is the sesquiterpenoid, helenalin. The Commission E reports that, when applied topically, arnica preparations have strong anti-inflammatory activity. In cases of inflammation, arnica also shows analgesic and antiseptic activity. In animal studies, helenalin has analgesic, antibiotic, antimicrobial and anti-inflammatory activity.

The tincture has been used as a gargle or mouthwash for mouth and throat inflammation, particularly in its homœopathic form.

Antimicrobial activity

Arnica has shown both antimicrobial and antifungal activity against a range of organisms such as listeria and salmonella, as well as Staphylococcus aureus (golden staph), mainly through its chief active ingredient, helenalin.

Immunostimulant activity

Helenalin has also been shown to stimulate the immune system in vitro, while the polysaccharide components have been shown to stimulate the immune system in vivo.

Arnica also contains an adrenalin-like precursor and possesses cardiotonic activity.

Clinical studies

There are limited clinical studies on humans, but one successful study showed that a preparation of arnica flowers was more effective than placebo in treating muscle aches and pains. Arnica was also shown to be better than placebo in achieving improvement in venous tone, oedema (swelling) and a feeling of heaviness in the legs. Clinical trials have indicated that Arnica montana fresh plant gel, when used topically, can reduce symptoms of osteoarthritis.

Side effects & contraindications

Herbal preparations of arnica are potentially poisonous if taken internally as they are strongly irritating to mucous membranes. This can lead to severe gastroenteritis and muscle paralysis (including cardiac), and can generate symptoms of palpitations and shortness of breath, and may even lead to death — largely due to the toxic effects of helenalin.

Arnica is considered much safer when used topically, although there have been a few reports of dermatitis using the creams where it can trigger sensitivity to contact allergens.

Arnica is contraindicated in the treatment of rheumatoid arthritis, as in some cases it can increase macrophage-induced local inflammation. It’s also contraindicated in pregnant or breastfeeding women and those who are allergic to, or have a known hypersensitivity to, members of the daisy family, including chamomile and marigold.

With today’s knowledge, topical arnica preparations should not be used on broken skin (such as wounds and cuts) but is safe and effective for sprains, strains, swellings etc.

Arnica should never be taken internally except in homœopathic preparations.