Arnica salve is a skin-healing product made with the flower and sometimes the rhizome of the arnica montana plant. In Europe and Central Asia, arnica has been used since the 16th century to soothe minor skin afflictions and muscle aches. Native Americans also used the flower for medicinal purposes.
Arnica montana is a flower that is native to the mountains of sub-Arctic regions, including Northern Europe, Central Asia, Canada, and the northern U.S. The flower is bright, deep yellow and shaped similarly to a daisy, with fuzzy stems and sparse foliage. Other common names are wolfsbane, mountain tobacco, leopard's bane, and mountain daisy. Flowers for medicinal preparations are harvested in late spring shortly after blooming, and rhizomes can be collected in late fall when the plants have died back.
Arnica may be used as a tincture or a salve. Arnica tincture is made by steeping the flowers in ethanol for several weeks, then straining out the plant material. Diluted tinctures might be used directly on the skin or in poultices or compresses. The salve is made by mixing the tincture into a carrier oil or a thicker preparation made with beeswax thinned with oil or another product like petroleum jelly or lotion.
When used on minor skin afflictions such as small wounds or bruises, arnica salve can reduce swelling and speed healing. Its healing properties believed to be due to constituents of the flower such as helenalin, an anti-inflammatory that helps prevent edema. In vitro studies have shown the flower also has some anti-microbial activity.
Arnica salve is also effective at reducing muscle pain and aches from trauma, over-exertion, and sprains. Topical preparations reduce swelling and possibly increase the circulation around the area, which soothes the pain and swelling. Some marathon runners apply arnica salve before a race to prevent pain and reduce stiffness while running. Arnica is also available in homeopathic remedies that are taken internally to treat or prevent muscle aches as well as migraine headaches.
Unless the arnica is in a highly diluted homeopathic preparation, it should never be taken internally. The plant is toxic in high doses. Lower doses can cause dizziness, nausea, heart palpitations, or tremors. Arnica salve should also not be used on broken, weeping skin or skin ulcers because of the possibility of entering the bloodstream. Some people have skin reactions to arnica, including rashes, eczema, and itching. External side effects like these are more likely with frequent, long-term use.