Arnica salve

Arnica salve is made by heating one oz. of the flowers in one oz. of lard.

Illustrated Phytotherapy by Thomas Deschauer - 1942

Arnica montana

Specific Indications. - Muscular soreness and pain from strain or overexertion.

Action and Therapy. - External. Arnica, in tincture or fomentation, has long been a popular but by no means safe discutient to prevent and discuss inflammatory swellings, and to relieve the soreness of myalgia and the effects of sprains, bruises, and contusions. It is often serviceable to remove ecchymoses, and it gives grateful relief to sore muscles that have undergone much strain and exertion.

The Eclectic Materia Medica, Pharmacology and Therapeutics by Harvey Wickes Felter, M.D. (1922)

Uses and toxicity

Arnica montana is sometimes grown in herb gardens and has long been used medicinally. It contains the toxin helenalin, which can be poisonous if large amounts of the plant are eaten. Contact with the plant can also cause skin irritation. The roots contain derivatives of thymol, which are used as fungicides and preservatives and may have some anti-inflammatory effect. When used topically in a gel, Arnica was found to have the same effect as the use of NSAIDs (ibuprofen) in treating the symptoms of hand osteoarthritis. A study found that the application of topical Arnica had no better effect than a placebo in the treatment of laser-induced bruising.

Arnica is currently used in liniment and ointment preparations used for strains, sprains, and bruises. Commercial arnica preparations are frequently used by professional athletes. The thymol derivatives concentrated in the plants' roots have been clinically shown to be effective vasodilators of subcutaneous blood capillaries. Arnica preparations used topically have been demonstrated to act as an anti-inflammatory and assist normal healing processes by facilitating transport of blood and fluid accumulations through a dilating action of subcutaneous blood capillaries. If ingested internally, the toxin helenalin produces severe gastroenteritis, and internal bleeding of the digestive tract if enough material is ingested.