The COVID-19 coronavirus pandemic is the most significant public health event of a generation. Its worldwide spread has totally disrupted our old (early 2020) way of life. At time of writing there are 5.5 million confirmed cases and 350,000 deaths, across 217 countries. A vaccine, if an effective one is ever developed, is many months (more likely years) away. This is the most frightening event many people may ever have experienced. While we now understand a lot about the structure of virus itself, there are many aspects of COVID infections that remain unclear, including transmission and treatment. Uncertainty is frightening, but that is what we are dealing with. Different countries are taking different approaches. It is not surprising that in the absence of robust science and consistent public health advice, COVID pseudoscience has exploded.

Quackery, or health fraud, is a health practice that is ignorant or fraudulent. It can include a diagnosis, a test, or a treatment. A quack is someone that promotes these types of therapies. However, just because something is unproven does not make it quackery. An absence of evidence does not mean evidence of absence. Plausibility matters. The contributors to this blog are Bayesians which in short means that our assessment of “new” data, evidence, or claims is informed by the existing evidence; this includes, in the case of medicine, our understanding of basic science. In evaluating a medical claim, we ask, “Is this plausible, based on what we already know?” It is no different in a pandemic with a novel virus. In the case of COVID, while much is unknown about the infection, there is also a tremendous amount that is known – including human biochemistry, physiology, coronaviruses (in general), and how virus-based infections are transmitted or can be prevented.

Plausible therapies that are unproven may not be quackery. They could be considered experimental until better evidence emerges. However, many therapies that are currently being promoted for COVID-19 are clearly quackery. Unbound by evidence and driven by a combination of ignorance, hyperbole and usually grift, the number of products and interventions touted as useful to prevent or treat COVID infections continues to grow. Here is a list of what I’ve encountered so far, and a bit about each one where there is some information to share. If I missed anything, please leave it in the comments, and I’ll do a follow-up or add to this list over time.


If you asked me in March, I wouldn’t have put this on the list. Hydroxychloroquine started out as perhaps weakly plausible based on poor, but promising, evidence. But as more and more evidence has emerged, it is now difficult to accept that there is any “there” there. Not only is there no evidence of benefit, there is now increasingly convincing evidence of harm. If this therapy was simply abandoned given it is ineffective, it wouldn’t be quackery. While some clinical trials are being shut down, it continues to be prescribed and promoted despite the lack of any convincing evidence it can prevent or treat COVID infections. That’s why it’s becoming quackery. Outside of an ongoing clinical trial, there is little rationale for its use. David Gorski has more in posts here and here.

Bear bile and other forms of Traditional Chinese Medicine (TCM)

Despite the Chinese government’s endorsement and promotion of bear bile injections and other forms of TCM, there is no credible evidence that it is effective. Bear bile extraction is exceptionally cruel, as Jann Bellamy documents, and there is no proven role for TCM in COVID. The tactics on display by the Chinese government are part of an ambitious strategy by the Chinese government to build the reputation of TCM as equal to “Western” medicine. Yes there are papers in the scientific literature that tout TCM. Regrettably, one of the biggest enablers and promoters of TCM outside China is the World Health Organization.

Bleach (when ingested)

I’ll set aside the more obvious warning about injecting disinfectant to mention a more pernicious quackery that has been around for some time. Chlorine dioxide is an industrial bleach product that has been promoted for years as a medical product. Branded as “Miracle Mineral Solution” or “MMS“, this blog has covered this quackery extensively. It is now being promoted as a COVID treatment by conspiracy theorists and grifters. The FDA has issued warning letters to vendors.

Colloidal silver

Colloidal silver has been covered previously at Science-Based Medicine. Silver is used medicinally in some drug products and devices, but when consumed will not have any beneficial antiviral properties. It can, however, turn you blue.

Chaga mushroom blends

I had a delicious tea today. It contained chaga mushrooms. I bought it for an alternative to all the coffee I’ve been drinking, and didn’t realize it’s also touted as some sort of anti-viral. Even for a fungi, chaga doesn’t look that attractive, and I gather it has a long history of unwarranted fame as some sort of health panacea (spoiler alert: probably not). While some manufacturers claim chaga will help with your immunity, there is no credible evidence to substantiate these claims.

Oil of oregano

Oil of oregano has been a perennial quack remedy for more than a decade. It is perhaps not surprising that it’s being positioned as an antiviral. Which I supposed it could be, if you dripped the oil directly on a virus. I get emails regularly touting how oil of oregano is effective, based on in vitro (petri dish) studies. But by that argument, drinking margaritas should be an effective COVID strategy, because alcohol-based hand sanitizers are indeed antiviral, when used properly. Doses matter. The delivery method matters. By consuming it, we dilute it, and it’s not going to have any meaningful effects. Save your oregano for your pizza.


Homeopathy is the air guitar of medicine – it looks like a drug, but it’s usually just pure water (sometimes sprayed on little balls of sugar). Not surprisingly, it hasn’t been shown to be effective for any medical condition, except perhaps thirst. Despite its German origins, homeopathy is big in Cuba. Edzard Ernst noted that homeopathy is being given in Cuban eldercare facilities, apparently to protect against COVID infection.

Aquarium water (drinking it)

Despite a CBC story that cautions against it, I couldn’t find any other endorsements of this admittedly bizarre strategy. It may be referring to the consumption of the drug chloroquine which is sold for the treatment of various fish infections. Consumption can be fatal. Chloroquine is not the same as hydroxychloroquine, but both seem ineffective at treating COVID infections. See also the tonic water, below.


Zinc has been touted as a cold remedy for decades, but the evidence supporting these claims is mixed. If it does work, the effectiveness is modest and side effects are common. A chiropractor made a video touting tonic water (see the next item) and zinc which apparently garnered 21 million views. There is no credible evidence to support the claim that zinc has any role in preventing or treating COVID infections.

Tonic water

This may be based on confusion between chloroquine (no evidence for COVID) and quinine, a completely distinct drug. Both have roots as anti-malarial medications but your more common exposure to quinine is the tiny amount added to tonic water. Interestingly, tonic water used to be medicinal, but there is no reason to expect that today’s tonic water will have any health benefits, unless you derive medicinal benefits from its combination with gin.

Chiropractic adjustments

Jann Bellamy covered this in a prior post. In some jurisdictions, regulators have taken action against chiropractors who are making claims about the effectiveness of chiropractic adjustments for preventing COVID infections. You can’t “boost” your immune system with chiropractic, or any other physical intervention, for that matter.


Harriet Hall blogged about this at the end of December 2019 (how long ago that feels now) and she felt the evidence for elderberry product was promising, but that more research was required. Like a lot of natural-based products, the active ingredient (if there is one) hasn’t been identified, and the products may not be free of side-effects. While some cold viruses are coronaviruses, there is no research that examines elderberry and COVID.

Juice fasting

Juice can be delicious but existing solely on juice sounds like some form of punishment. Depriving your body of a balanced diet isn’t a good idea even when there isn’t a pandemic. Why put your body at risk through dietary deficiencies?


Drinking methanol is a bad idea for any reason. Methanol is not ethanol. This quackery has killed over 700 Iranians so far. If it doesn’t kill you, it may leave you blind.

What’s missing?

The COVID-19 pandemic is evolving quickly, and I have no doubt that I am only scratching the surface of the implausible therapies being promoted to treat or prevent infections. Did I miss anything? Let me know in the comments. I’ll give a special SBM prize for the most bizarre, implausible COVID quackery someone can find.


Posted by Scott Gavura