Arnica Montana: Toxic? Nontoxic? Sometimes toxic?
October 29, 2022 9:22 AM   Subscribe

My wife's been using arnica tablets labeled "30C HPUS" to treat pain, and has reported good effects; she also uses topical arnica gel which actually contains arnica. What with the oral tablets helping her in spite of containing no active ingredients, it seemed to me that oral tablets which, y'know, actually contained detectable levels of arnica (which 30C HPUS dilutions do not) might help, but a lot of what I'm finding suggests (somewhat ambiguously) that arnica is toxic.

So, on the "arnica will kill you and everything you love" side, you have literally every single resource discussing undiluted arnica, which says (without any reference to specific dosages) that taking arnica orally is a terrible idea. Drug/herbal regulatory authorities pretty much everywhere seem to specifically describe oral arnica as "unsafe". I read and tend to trust these resources, which seem to be in fairly consistent agreement although I'm bugged by the fact that nothing on there discusses actual quantitites at all, whether of specific chemicals or of herbal material; "dangerous at any dosage" seems to be the consensus but there aren't any case-studies I find along the lines of "a 120-pound male ingested three cups of tea brewed from a 0.5oz teabag and had this-that-and-the-other symptoms", which seem to be pretty common when there are substantiated horror stories about things people do not realize are toxic.

On the "arnica is not going to kill you" side, there are a wide range of products which seem to actually contain arnica sold for oral consumption which do not seem to figure into horror stories of them killing and/or causing serious disability to people. Some of this might be different species: AFAICT most of the teas being sold contain not Arnica montana but Heterotheca inuloides (a.k.a Mexican arnica). But there are, for instance, MauWe herbs 600mg capsules, which explicitly claim Arnica montana extract (600mg, which seems like a potentially substantial quantity) and nowhere suggest a homeopathic dilution.

It seems that in the matter of extract specifically, there's some science which suggests nontoxicity: A PubMed abstract on arnica toxicity specifically describes the extract as nontoxic, although nowhere in the extract is oral administration specifically described. Searching for specific lethality of specific doses also brought me to a Norwegian health-and-safety report citing that same article reporting an oral LD-50 of more than 5 g/kg in rats, which doesn't seem very dangerous, and focusing more on potential allergic skin reactions.

So I'm now extremely confused. Is oral arnica safe? Is it unsafe? Is it safe only in a macerated extraction and unsafe in flower form? Are the herbal-dosage arnica tablets sold on the market (a) actually homeopathic-dosage without being labeled as such, (b) extremely dangerous, or (c) somehow full-strength but safe? I would like to see if I can help my wife with muscular pain relief without poisoning her (or paying medicine prices for sugar tablets).
posted by jackbishop to Health & Fitness (8 answers total)
 
Here's the German Commission E monograph on arnica flower. I'm not sure, but I think the Commission E monographs were basically "here are the traditionally-used herbs that we don't really know enough about but we feel like we need an official opinion". It is listed as an approved herb.

Here is a longer, more detailed and recent article on arnica, with citations. My favorite paragraph is the last one.
posted by aniola at 9:35 AM on October 29, 2022 [1 favorite]


The Wikipedia article on helenalin, the main toxin in Arnica, gives sources that cite lethal dosage in animal studies at least. I assume the fact that lethality and high liver toxicity in humans has been already noted precludes further human experiments from being ethical.

Also note that herbs are notoriously uneven in how much of the active ingredients they contain - it depends on weather, soil, sun exposure and many other factors. I wouldn't play liver roulette with plant extract.
posted by I claim sanctuary at 10:16 AM on October 29, 2022 [1 favorite]


It sounds like you know this already, but something labeled "30C" is, in fact, a placebo pill. That is a 10^60 dilution, which, per Wikipedia (I have not checked the math) is the same as giving two billion doses per second to six billion people for 4 billion years to deliver a single molecule of the original material to any patient.

I'd be less worried about liver toxicity from a topical application. Apparently the stuff is carcinogenic, but again, if you're talking a similar dilution as the oral compounding, that's less cancer risk than eating a banana.
posted by basalganglia at 10:30 AM on October 29, 2022 [1 favorite]


Response by poster: Mmm, getting a (significantly lower than the cited extract toxicity) LD-50 for helenalin alone at least helps quantify risks. The Norwegian report in my original question actually has a little section on helenalin, I see, with a reported ingestion of 30g causing "severe illness but not death", and a reported death after a "70g tincture of Arnica montana", which somewhat contextualizes my alarm about the acute toxicity of, say, these 600mg tablets (in which, presumably, that 600mg is not pure helenalin).

Vis-a-vis the topical application, she uses a 25% (25g per 100g tube) cream. Unless they're hiding it very well in the packaging information, this is not a homeopathic preparation. Her lack of negative response to it indicates she doesn't have a dermal sensitivity/allergy, which is apparently not uncommon, but that's not necessarily relevant to the issue of safely taking an oral preparation.
posted by jackbishop at 11:04 AM on October 29, 2022


Substituting someone's pills secretly with other pills you purchase online and place in the same bottle is extremely bad advice, not a respectful or ethical thing to do to an adult, toes the line of gaslighting, and has the potential to utterly destroy the trust in a relationship.
posted by lizard music at 2:37 PM on October 29, 2022 [16 favorites]


This is the whole thing about homeopathy.

Homeopaths began with this principle of "like cures like": if a patient is suffering from some symptom, and they ingest substance that provokes the same symptom, it will relieve the symptom. So, arnica rubbed into your skin made your skin hurt, then taking arnica should cure pain generally. Which, considering the state of pharmacological knowledge at the time might have seemed as good a guess as any.

But as homeopaths found two interesting things:
1) That many of these substances had bad side effects.
2) That diluting the substances (i.e. reducing the dose), while reducing the side effects, somehow didn't seem to decrease the effectiveness of their preparations.

Evil Big Medicine looked at #2 and concluded that these preparation were only as effective as placebos.

Homeopaths looked at #2 in combo with #1 and decided that diluting more made medicines better—just as good, but less toxic.

And eventually they found:

3) That these new extremely extremely diluted preparations worked even better.

EBM looked at #3 and concluded that patients saw bigger, more fancier-looking numbers on the label and heard about the more extensive processes that went into making these preparations and decided the more dilute preparations were better, improving the placebo effect.

Homeopaths looked at #3 and decided that MOAR DILUTION GOOD and eventually formed a hypothesis that shaking water molecules in proximity with other chemicals gave the water "memory" of the original chemicals that can then somehow affect the patient's body—an idea that flies in the face of everything we know about chemistry.

So, NO, replacing placebo pills that likely contained not one molecule from the arnica plant with actual arnica in pill form is NOT likely to help your wife's symptoms, because oral arnica was NEVER PRESENT.

The topical arnica is working because it creates a sensation of heat in the tissues, which helps to relax muscles and distracts one mentally somewhat from pain in the local area. In addition, it may have anti-inflammatory effects. None of this suggests—and there is no data to show—that taking arnica orally would reduce pain.

Plus it's toxic. So don't eat it.
posted by BrashTech at 5:17 PM on October 29, 2022 [4 favorites]


Substituting someone's pills secretly with other pills you purchase online and place in the same bottle is extremely bad advice, not a respectful or ethical thing to do to an adult, toes the line of gaslighting, and has the potential to utterly destroy the trust in a relationship.

This. And No, it is in my opinion not at all okay to make such a suggestion ever, not even for "for the purpose of putting an inconsequential pricing issue into its proper perspective."</em No, this is Not helpful to either asker or their spouse.
posted by 15L06 at 3:53 AM on October 30, 2022 [1 favorite]


Mod note: A couple deleted. flabablet I've given you the day off, and the next time will be a week, and then total ban. Ask Metafilter is not your playbox, it's not someplace to hear yourself talk tough and try to show off. Ask Metafilter is for helping the OP, so giving what you yourself say is "obviously terrible advice" does not meet the brief. Do. Not. Do. This. You need to restrain yourself.
posted by taz (staff) at 7:23 AM on October 30, 2022 [2 favorites]


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