Arnica 30C

Arnica is one of the oldest things in an Australian first aid drawer. These are the questions our naturopaths ask in store, and they come down to which of the two products you're holding and where on your body it's going.

A good fit if

• You've had a knock, a sprain or a heavy training session, and the skin over it is unbroken
• You want something you rub on rather than swallow, which is where the trial evidence is
• You'll choose by the strength shown on the pack, because a percentage or extract ratio tells you what you're getting
• Daisy-family plants have never bothered you and you're not putting it near broken skin

Check with us first if

• You're pregnant or breastfeeding. There's no clear position either way, Australian rules don't require a pregnancy warning, and the safety panel that reviewed it had no data on effects on pregnancy or development. That makes it a conversation with a practitioner, not a decision to make at the shelf.
• You take a blood thinner or antiplatelet medicine. It's the question we're asked most about arnica, and there's no good evidence either way, so the honest answer is to ask your doctor or pharmacist first.
• You have surgery or a dental procedure coming up. Arnica is widely used around operations and the results are mixed, so anything you use around a procedure needs to be cleared by the person doing it.
• You get hay fever or react to other flowering plants. The daisy family is large, and arnica is one of the plants that causes skin allergy fairly often.
• You're using it day after day rather than for a few days. Skin allergy to arnica is a delayed reaction, so it can appear after repeated use rather than the first time.
• You take any prescription medicine. Check with your doctor, pharmacist or our naturopaths before starting.

• Herbal cream, gel or ointment (a material amount of arnica tincture or extract). Best known for: Bruises, sprains and localised muscle soreness, on unbroken skin. Absorption: An arnica tincture on intact skin passed readily into the skin and stayed in the outer layer, without reaching the bloodstream. Typical use: This is the half of the family the trials tested, and the results depend on the setting. Strength varies a lot between products and it's the number that matters: the trial that found nothing used a 10% ointment, while the hand trial used a gel of 50 g tincture per 100 g, at an extract ratio of 1:20.
• Arnica-infused oil. Best known for: Massage, the traditional way it was applied. Absorption: Not separately studied in the research we reviewed. Typical use: A traditional preparation made by steeping the flowers in a carrier oil. The strength usually isn't stated, and none of the trials we reviewed used an infused oil.
• Homeopathic tablets, pillules, drops and oral sprays (6C, 30C, D30, 30X). Best known for: The form most Australians actually take by mouth, around knocks, dental work and sport. Absorption: Not applicable. These are diluted so far that almost no arnica is left, by design. Typical use: Long tradition rather than trial support. The largest trial in the family, 400 runners on 30X, found nothing, and the pooled surgery studies don't reach significance. Don't assume the cream results apply to these.
• Homeopathic topical cream or gel. Best known for: Looking exactly like the herbal creams and gels on the shelf. Absorption: Not applicable, for the same reason. Typical use: A quick way to tell: a stated potency (6X, 30C) means homeopathic, while a stated percentage or extract ratio means herbal. The herbal evidence doesn't carry across that line.
• Herbal arnica taken by mouth, and 'arnica' that isn't Arnica montana. Best known for: Neither is what you want. Absorption: Not applicable. Typical use: Australian rules cap any use other than on the skin at 1 mg of dried herb equivalent a day, so a herbal dose by mouth isn't allowed in a listed medicine, and swallowing herbal amounts of arnica is dangerous. Brazilian arnica is Solidago chilensis, a different plant, and in Spain and Portugal 32 species share the name. Check the botanical name.

Reference values. There isn't one. Arnica is a herb, not a nutrient, so there's no recommended intake, no deficiency and no dietary requirement to meet.

Typical supplemental range. For creams, gels and oils, follow the directions on the pack, because strength varies so much between products. In trials, people used an ointment twice a day under a dressing for two weeks, a gel for 21 days, and a tincture three times a day for up to 45 days. Homeopathic products state a potency rather than a dose of herb.

Upper level. For use on unbroken skin, Australia's permitted ingredients list (Schedule 1) sets no maximum daily dose. For any other use, item 682 says: 'When for use other than topically on unbroken skin, the maximum recommended daily dose must be no more than 1mg of the equivalent dry herbal material of arnica montana.' One milligram of dried flower is a pinch of dust, which is why arnica you take by mouth here is homeopathic.

Worth knowing. There's a clearer rule for how long than for how much. European guidance says that if symptoms last longer than 3 to 4 days, or get worse while you're using it, stop and see a doctor or qualified health practitioner. What you need depends on your age, diet and health, so talk to one of our naturopaths.

Food first, where the diet allows it.

• None. Arnica isn't a food and has no dietary sources: it's a toxic plant in herbal quantity: ingestion of arnica-containing products has induced severe gastroenteritis, nervousness, accelerated heart rate, muscular weakness and death. The only reason anyone takes it internally is as a homeopathic dilution

If any of these sound like you, talk to one of our naturopaths or your doctor before you start.

• You're allergic or sensitive to daisy-family plants (Compositae/Asteraceae), such as daisy, ragweed, chrysanthemum, chamomile, echinacea or feverfew. Arnica can cause a delayed (type IV) allergic skin reaction, reported in people who handle the flowers and linked to compounds called sesquiterpene lactones.
• You'd be applying it to broken skin, open wounds, eyes or mucous membranes. Schedule 1 only allows unrestricted use on unbroken skin; anything else falls under the 1 mg a day cap.
• You'd be swallowing arnica in herbal (non-homeopathic) amounts. Taking it by mouth has caused severe gastroenteritis, nervousness, a fast heart rate, muscle weakness and death.
• Children under 12. The EU herbal monograph limits arnica flower medicines to adults and teenagers from the age of 12.
• You're pregnant or breastfeeding. There's no evidence either way: no pregnancy warning applies to the Australian ingredient items, and the Cosmetic Ingredient Review panel had no cancer, reproductive or developmental toxicity data. See a practitioner rather than assume it's fine.
• You take an anticoagulant or antiplatelet medicine, or have surgery or dental work coming up. We found no interaction study, so check first rather than assume it's fine.
• You use it on your skin repeatedly. Allergic reactions reported with arnica flower medicines include itching, skin redness and eczema; how often they happen is unknown.
• Your symptoms last more than 3 to 4 days or get worse while you use it. The European monograph says to see a doctor or qualified healthcare practitioner.
• You expect one arnica product to work like another. Composition varies with where the plant was grown, extracts can carry heavy metals, and one extract was mutagenic in a lab (Ames) test, which the safety panel listed as an unresolved data gap.
• The product says 'arnica' with no botanical name. Brazilian arnica is Solidago chilensis, a different plant that isn't on Schedule 1, and 32 species in Spain and Portugal share the common name.