Which species is “Arnica”?
“Árnica” in Mexican and US-Hispanic commerce is usually Heterotheca inuloides — a different genus from the European Arnica montana of homeopathic and topical tradition.
The species behind the name
- Arnica
Arnica montana
Arnica montana — the European species; helenalin-type sesquiterpene lactones; topical-use tradition with documented oral toxicity.
- Mexican Arnica
Heterotheca inuloides Cass.
Heterotheca inuloides (Mexican arnica) — the árnica of Mexican herbolaria; different genus and different chemistry (cadinane sesquiterpenoids).
How to tell what a product actually is
- Market origin is the cue: árnica sold in Mexican commerce or US-Hispanic markets is usually Heterotheca; European-labeled products are A. montana.
- Both traditions are topical-leaning; neither species' name on a label establishes the other's research record.
Educational use only. This page explains species identity — it makes no claim that any species works for anything, and it is never a place to decide what to take. It is not a substitute for medical advice. If you take medication, talk to your clinician or pharmacist before adding any botanical, whichever species it turns out to be.