Arnica

Botanical

What is it

Arnica (Arnica montana, and related Arnica mollis) is a perennial herb whose flowers are used topically for bruises, sprains, and muscle soreness. Homeopathic arnica is also available orally.

Evidence for 1 use

AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.

Bruising / muscle soreness (topical)

Limited Evidence

Small trials of topical arnica preparations show modest reductions in bruising and post-exercise soreness; evidence is mixed.

How it works

Arnica flowers contain sesquiterpene lactones (helenalin), flavonoids, and essential oils. Topical helenalin has demonstrated anti-inflammatory activity in animal models, potentially via NF-kB inhibition. Oral arnica at herbal doses is potentially toxic; homeopathic oral preparations contain negligible amounts of the active. Topical preparations are the most commonly used and best supported form.

Dosage

There is no RDA. Topical creams and gels are applied 2-3 times daily; homeopathic oral doses contain trace amounts. Herbal-strength oral use is not recommended. DSLD does not provide a median dose for this entry.

When and how to take it

Topical: apply after injury 2-3 times daily for short periods. Homeopathic: per product directions.

2 commercial forms

Compare the main delivery options and what they’re best suited for.

Topical arnica gel / cream

Most commonly used and best-supported form.

Local action; limited systemic absorption.

Homeopathic arnica (oral)

Used orally at homeopathic potencies.

Highly dilute; essentially no measurable arnica content.

Safety

Topical use is generally well tolerated but can cause contact dermatitis, especially with prolonged use. Oral herbal-strength arnica is considered toxic and can cause cardiovascular and GI symptoms. Homeopathic dilutions are considered safe due to negligible active content.

Who should be cautious

Avoid herbal oral arnica entirely. Avoid topical use on broken skin. Caution in Asteraceae (Compositae) allergy. Pregnancy/breastfeeding: avoid internal use.

Interactions

Topical: limited systemic interactions. Avoid oral herbal-strength preparations.

Frequently asked questions

Can I take arnica orally?⌄

Only in homeopathic dilutions. Herbal-strength oral arnica is potentially toxic.

Does arnica really help bruises?⌄

Topical arnica may modestly reduce bruising and soreness; evidence is mixed but generally supportive for limited use.

References

Arnica on Wikidata — Wikidata link

Arnica on NIH DSLD (US supplement label database) — NIH Dietary Supplement Label Database link

Research on Arnica (PubMed search) — PubMed link

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Evidence-based·How we grade evidence

Disclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you’re pregnant, breastfeeding, on medications, or managing a chronic condition.