The Arnica montana, or leopard's bane, grows in Northern Europe and Asia and in the Northwestern United States. The dried flower heads contain alkaloids, an essential oil, resins, and an ammonia compound, trimethylamine, none of which are separately recognized by the U. S. P.

Externally arnica is stimulating and irritant, increasing the circulation of the skin. It sometimes causes excessive redness, and eczema, and must be used with care.

The diluted tincture promotes the absorption of blood which has effused into the tissues, as after a blow, and prevents swelling.

Internally, in small doses, arnica is slightly stimulating to the heart, the skin, and kidneys.

In larger doses it is a cardiac depressant, and in doses equal to ℥ i. of the tincture it has caused the poisonous symptoms of gastro-intestinal irritation; cold dry skin; feeble fluttering pulse, lowered sometimes to 6o; and occasionally vomiting and purging, with final collapse. It should never be applied to an open wound.

Preparations

Tinctura Arnicae. Tincture Of Arnica

Strength, 20 %.

This preparation used externally must be diluted, applied on a piece of flannel to the inflamed part, and covered with a bandage.

Average dose,  xv.-i mil.