Hairy Arnica (Arnica mollis), like its close relative Arnica montana, has a longstanding history of traditional use for external application to support the healing of minor injuries such as scratches, abrasions, and bruises. Indigenous peoples and folk medicine practitioners in North America have utilized arnica preparations—often as poultices or ointments—to soothe trauma to the skin and underlying tissues. The rationale for its use centers on its perceived anti-inflammatory and analgesic properties, attributed to compounds such as sesquiterpene lactones and flavonoids found in the plant.

However, scientific research has focused primarily on Arnica montana, with minimal direct clinical data available for Arnica mollis (Hairy Arnica). The evidence for topical arnica preparations in general is mixed: some small trials with Arnica montana suggest modest benefits for bruising and postoperative swelling, but robust, high-quality clinical trials are lacking, especially for abrasions or scratches. Safety data indicate that topical arnica can sometimes cause allergic reactions or irritation, especially if applied to broken skin.

In summary, the use of Hairy Arnica for scratches and abrasions is based primarily on traditional practice, with little direct scientific validation for efficacy or safety in this context. Its use persists in herbal medicine, but caution is advised due to potential for skin irritation.