Arnica is a hardy perennial in the aster family (Asteraceae) which grows at elevation in the subalpine meadows and open forests of mountainous regions. A. montana is native to Europe and also grows in northern Alaska and British Columbia, whereas A. cordifolia and A. latifolia predominate in the Western United States (Gladstar, 2000). Due to overharvesting, A. Montana should not be wild harvested, and harvesting of the North American species should be limited. A. chamissonis is native to the United States and is cultivated as a substitute for A. Montana at low elevations. There are several other species as well, but all seem to have similar medicinal uses.
Arnica has daisy-like yellow flowers consisting of a central disk of florets surrounded by the showy ray florets. The flowers are 1 to 4 inches in diameter and bloom starting the second year (Gladstar & Hirsch, 2000) in June through August. The erect, sturdy stem is up to two feet tall and has a rosette of basal ovate-shaped leaves near the ground and opposite pairs of downy lance-shaped leaves upon the stem. In fact, the name arnica is derived from the Greek word arnakis, meaning “lamb’s skin” (Gladstar & Hirsch, 2000), referring to these downy or wooly leaves. Arnica grows in colonies from a horizontally spreading rhizome.
The fresh flower heads are harvested and used fresh or dried to make a tincture or an infused oil or salve.
Arnica contains sesquiterpenes, flavonoids, tannins, volatile oils, resins, and bitters (Hoffmann, 2003). Foster and Tyler (1999) report that sesquiterpenoid lactones (including helenalin) are the active ingredients in arnica, accounting for its anti-inflammatory, analgesic, and antibiotic effects. Energetically, arnica is considered warming and drying. It is a plant of the sun, after all!
According to The Herbarium:
“Arnica is known as an injury remedy, and has been used for thousands of years in the European Alps and by Native Americans (Holmes, 1997). It is an anti-inflammatory, analgesic, vulnerary, and rubifacient herb used to speed healing and relieve pain, inflammation, swelling, and bruising associated with traumatic injuries such as fractures, sprains, and contusions. It is renowned for treating muscular pain from overexertion and is an invaluable ally for athletes or anyone else who puts in a hard day’s work and has the aches to show for it. Gladstar & Hirsch (2000) also recommend it for back pain, rheumatic pain, dislocations, and varicose veins. For injuries, aches, and pains, it can be used topically on unbroken skin as a poultice, liniment, compress, oil, cream or salve or homeopathically. No first aid kit is complete without arnica!
Homeopathically, arnica is very safe and is used to support healing in the case of shock, post traumatic stress disorder (PTSD), post surgical trauma, invasive dental work, and concussion in addition to its aforementioned use for injuries and muscle strain (Gladstar & Hirsch, 2000).
Arnica was also historically used as a cardiac restorative and coronary circulation stimulant (Holmes, 1997). Those internal uses will not be elaborated here because arnica can be toxic to the heart and circulatory system (Foster & Tyler, 1999) and must either be avoided or used with extreme caution and only under the close supervision of a qualified herbalist.”
Poultice: Use externally as needed.
Salve: Use externally as needed.
Infused Oil: Use externally as needed.
Externally, arnica is generally safe when applied to unbroken skin, however its constituent helenalin may cause contact dermatitis in some people, causing pain, itchiness, and inflammation. Arnica should not be taken internally. Homeopathic arnica is considered safe.