In my previous blog I discussed recent research on cannabis’ role in maintaining healthy teeth and gums. Cannabinoids appear to kill bacteria in dental plaque better than some common oral care products like Oral B and Colgate toothpastes. Well, there is now new (and very preliminary) research that indicates oral cannabis may help prevent COVID-19 from getting a foothold in your body.

OMG, can this be true? How, when, and who did this research? What is the explanation for these possible cannabis effects? What should we make of this for such a serious disease?

The article from Bo Wang, et al., is titled, In Search of Preventative Strategies: Novel Anti-Inflammatory High-CBD Cannabis Sativa Extracts Modulate ACE2 Expression in COVID-19 Gateway Tissues. The authors are associated with the University of Lethbridge and University of Calgary in Canada and was published online at on April 19, 2020. The article is not (yet) peer-reviewed (an important caveat). The work was done using C. sativa extracts on artificial human 3D models of oral, airway, and intestinal tissues.

As we all should know by now, the SARS-CoV2 virus that causes COVID-19, uses its spikes to gain entry into the human host by attaching to angiotensin-converting enzyme II (ACE2) receptors expressed in lung tissue, as well as oral and nasal mucosa, kidney, testes, and the gastrointestinal tract. The authors postulated that, “Modulation of ACE2 levels in these gateway tissues may prove a plausible strategy for decreasing disease susceptibility.” They hypothesized further that cannabis that is high in anti-inflammatory CBD might modulate ACE2 expression in COVID-19 target tissues.

The authors identified 13 high CBD C. sativa extracts that modulate (down-regulate) ACE2 gene expression and ACE2 protein levels. They also found that some C. sativa extracts also down-regulate serine protease TMPRSS2, another critical protein required for SARS-CoV2 entry into host cells. They conclude that their results, “lay a foundation for further in-depth analysis of the effects of C. sativa on the molecular etiology and pathogenesis of COVID-19, as well as other viral diseases in which viruses use the ACE2 receptor as a molecular gateway.” And, “may become a useful addition to the treatment of COVID-19, and an excellent GRAS [generally regarded as safe] adjunct therapy.” Certain C. sativa strains could be used to develop easy-to-use preventative strategies such as mouthwash and throat-gargle products that may be used in clinical practice and at-home treatment.

Now for some additional caveats to this study before we all start gargling our way to invincibility.

1. Not all cannabis strains used worked equally well. As the authors write so well:

“An exciting aspect of our study is that, while the ratios of the major cannabinoids (THC and CBD) are similar between the analyzed lines …, not all extracts were equally effective, and some produced undesired molecular effects. Such a finding emphasizes that medical cannabis is not generic, and each cannabis line has to be analyzed in detail to establish the ones that are the most potent.”

Sound familiar? We are left to guess which strains, i.e., chemovars, are possibly effective. No easy home-made mouthwash for us to make here.

2. It is not clear why they emphasize testing high-CBD chemovars. Could it be that the authors were more interested in less regulatory hassle? Witness their statement, “Most importantly, seven active lines have less than 0.3% of total THC and therefore can be classified as CBD Hemp in Canada and USA, allowing for easier implementation.” Clouding the picture is that some of the chemovars listed as effective had THC:CBD ratios as low as 1:1 and 1:1.5.

3. Luckily the authors used full-plant extracts to run their tests, but why did they not consider the acid (raw) forms of cannabis too, since cannabis acid forms are known for their strong anti-inflammatory properties? And although the authors recognize the complexity of cannabis and the entourage effect of the cannabinoids, terpenoids and flavonoids, we do not know which components have been lost in their extraction process. Could the link of some of the authors with a commercial company called Swysh, Inc., a cannabinoid oral health product developer, be a factor in all this?

So, my dear fans, when brushing your teeth with cannabis toothpaste don’t forget to gargle with cannabis mouthwash, in addition to hand washing, wearing face masks, social distancing, staying at home, and getting tested when feeling ill. Gargling might not help, but it probably does no harm either (GRAS!). And, who knows, it might help prevent bad breath too.

Stay healthy,

Dr. B.