Arnica montana, commonly known as arnica, is a perennial herb of the Asteraceae family. It grows mainly in mountainous regions of Europe and North America and is known for its medicinal properties, primarily as a topical anti-inflammatory. It is a flowering, aromatic, herbaceous and perennial plant. The flowering period is between May and August (Central Europe). It is distinguished by the large yellow flower of its blossoms. Arnica montana is used as a medicinal plant for analgesic and anti-inflammatory purposes.

Botanical description:

• Family: Asteraceae
• Genus: Arnica
• Species: Arnica montana
• Flowers: Its flowers are yellow or orange, have an intense fragrance and bloom in summer.
• Leaves: Its leaves are ovate and usually appear in pairs.

Cultivation
The flowers are collected when fully developed and dried without their stems. The roots can be harvested in autumn and dried after being carefully washed. Arnica Montana is also cultivated in botanical gardens and pots.

Name & Classification

The genus name Arnica comes from the Greek arni, “lamb”, in reference to the soft, hairy leaves of the plants. The Latin specific epithet montana refers to mountains or those originating from mountains. It is a moderately toxic European flowering plant in the daisy family Asteraceae.

Arnica Montana is widespread throughout most of Europe. It can grow even in poor, clayey soils that lack nutrients. It also grows in alpine meadows at altitudes of up to 3,000 meters.

Chemical composition The main constituents of Arnica montana are essential oils, fatty acids, thymol, pseudoguaianolide sesquiterpene lactones and flavanone glycosides; pseudoguaianolide sesquiterpenes (0.2–0.8% of the flower heads of Arnica montana), the toxin helenalin and their fatty esters.

Use in herbal medicine
Historically, Arnica montana has been used as an herbal remedy for centuries. The traditional uses of the plant are similar to those of willow bark and it is used for analgesic and anti-inflammatory purposes. Specifically:

• For pain and inflammation

• In fractures and bone regeneration

• In injuries, bruises and sprains

• In Homeopathy 

Clinical trials of Arnica montana have yielded mixed results:
When used topically in a gel at a concentration of 50%, Arnica was found to have approximately the same effectiveness as a 5% ibuprofen gel for treating symptoms of osteoarthritis of the hands.

Toxicity

Arnica should not be taken internally or used by mouth. The U.S. Food and Drug Administration has classified Arnica montana as an unsafe herb due to its toxicity. Arnica contains the toxin helenalin, which can be poisonous if large amounts of the plant are ingested or if concentrated preparations are used even in small quantities. It must not be taken by mouth or applied to open wounds where absorption can occur. Arnica irritates the mucous membranes and may cause stomach pain, diarrhea and vomiting. 

Consumption of Arnica montana may cause severe gastroenteritis, internal bleeding of the digestive tract, elevated liver enzymes (which may indicate liver inflammation), nervousness, accelerated heart rate, muscle weakness and death if ingested in large quantities.

Use according to the instructions of your doctor or pharmacist.