Arnica

Arnica montana

Snapshot

Indications	Contraindications
Post-rhinoplasty ecchymosis¹ Hand osteoarthritis² Knee osteoarthritis³ Bruises and sprains⁴ Muscle pain⁵	Asteraceae allergy⁴ Broken skin⁴ Pregnancy or nursing⁶

Arnica (Arnica montana) is a perennial sunflower-family herb whose flowers are used topically, where its sesquiterpene lactones inhibit inflammatory transcription factors⁵. Arnica is used for bruising and swelling after surgical or cosmetic procedures, for hand and knee osteoarthritis, and for muscle pain and sprains⁵.

Evidence is split by use. A Cochrane review found arnica gel in hand osteoarthritis probably similar to ibuprofen gel². After rhinoplasty, a meta-analysis found less eyelid edema and ecchymosis in the first week with arnica, though its authors called for better-designed trials to confirm this¹. A 2026 systematic review across surgical specialties found benefit in about half of studies, most often in plastic surgery⁷. A 2013 literature review listed arnica among herbal products that may contribute to hypertension and postoperative hematoma⁸. Products listing arnica are mostly liquid extracts, with gels, ointments, and tablets also sold; see Form comparison.

The most consequential caution is allergy: sensitization to arnica is relatively frequent among Compositae plants⁹. Per Memorial Sloan Kettering Cancer Center, patients taking warfarin are asked to talk with their healthcare provider because arnica may increase bleeding risk⁵.

Last updated October 16, 2026. Read how we make monographs.

In the full monograph

62 sources, 46 studies

When to useThe situations practitioners use it for, each with the reason and the study behind it.
SafetyWho should avoid it, who needs extra care, and the side effects reported in studies.
InteractionsThe medicines and supplements it interacts with, the effect of each, and what labeling says to watch.
Protocol notesThe doses used in studies, how and when they were taken, and how the forms on the market compare.
How it worksWhat it is and how it works in the body, in plain terms.
Published studiesThe studies behind each use, popular claims checked against them, and trials still under way.
Word of mouthWhat patients and practitioners report online, kept separate from the clinical evidence.
Clinical perspectiveA closing read of where the evidence is solid, where it is thin, and what has not been studied.

Snapshot

In the full monograph

Sources