Arnica montana                     Common name:  Arnica, leopard’s bane, wolf’s bane
Family: Asteraceae

Parts used: Flowers

Constituents: Sesquiterpene lactones (0.2%-0.8%, helenalin and its esters), flavonoids, volatile oil (thymol), coumarins, CHO (mucilage, inulin), amines, trace alkaloids

Medicinal actions: Wound antiseptic, vulnerary, anodyne, analgesic, immuno-stimulant, anti-inflammatory, astringent, counter-irritant, anti-rheumatic, antineuralgic, antiphlogistic (relieves inflammation)

Medicinal use: Arnica is reserved for TOPICAL USE ONLY. As an external agent is is useful for sprains, bruises, hematomas, edema, fractures, over areas of phlebitis and thrombosis, arthralgia and rheumatic joint pains, inflammed insect bites.  Arnica is most specific for bruises and may also be used as a massage oil to help relieve muscle soreness and stiffness.

Pharmacology:

• Sesquiterpene lactones (mainly helenalin) are highly toxic internally. Topically act as analgesic, antibiotic, anti-microbial, anti-inflammatory, immuno-stimulant.
• Volatile oils are counter-irritant, anti-inflammatory and vulnerary.

Pharmacy:  External use over intact skin only: Poultice or application of infusion 2g/cup or arnica oil (extracted at 1:5). Ointment: 10-25% of tincture (1:10, 70%), apply BID-TID.

Contraindications: Application over large areas of broken skin or internal use. Avoid with known allergy to Asteraceae family.

Toxicity: Internal use may result in gastroenteritis and with increasing dosage cardiac arrest due to helanin interfering with myocardial recovery in between contractions. With prolonged external use, edematous dermatitis may result with the formation of small vesicles.  Helanalin and its esters are sensitizing agents and act as allergens, can cause muscle paralysis & death.

Interactions: None reported.

Research: In lab experiments, helenalin has been shown to exhibit anti-inflammatory, analgesic and mild anti-bacterial properties. A 2002 clinical trial indicated that fresh arnica gel preparations successfully reduced symptoms (pain stiffness and decreased mobility) in patients suffering of osteoarthritis of the knee.