Oregano Oil Kills Norovirus—but Not Enough
Oregano oil cut numbers of the mouse version of norovirus 10-fold. Its active ingredient was better: a 10,000-fold reduction. But bleach achieves a million-fold reduction. Christopher Intagliata reports
By Christopher Intagliata
SUBSCRIBE TO Science Quickly
On supporting science journalism
If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.
Internet herb stores claim that swallowing oregano oil can cure your cold or flu. But the devil's in the details. Oregano oil is an antimicrobial, and can even kill off that tough cruise ship plague, norovirus—but there's no evidence it can do so inside your body, scientists say. It works to inactivate pathogens before they get inside.
Researchers experimented on the mouse form of norovirus—genetically similar to the hard-to-grow human strain. They treated virus colonies with solutions of either four percent oregano oil, or half a percent carvacrol—the active ingredient.
Turns out oregano oil cut virus numbers by 10-fold. Carvacrol: 10,000-fold. In comparison, bleach achieves a million-fold reduction. The results appear in the Journal of Applied Microbiology. [D. H. Gilling et al., Antiviral efficacy and mechanisms of action of oregano essential oil and its primary component carvacrol against murine norovirus]
So, oregano oil's nowhere near as effective as bleach. But it's nontoxic, and has no noxious fumes. Unless you hate the smell of oregano. So study author Kelly Bright of the University of Arizona says it could be useful in food-safety settings: “You could maybe reduce the amount of bleach you're using by throwing in some carvacrol or essential oil.” Just don't expect it to cure you, once you've got the bug.
—Christopher Intagliata
[The above text is a transcript of this podcast.]
Subscribe to Support Independent Journalism
Great science journalism requires human expertise, time, effort and creativity. And it costs money. That’s why I and the journalists here at Scientific American hope you’ll join our community.
When you subscribe, you are supporting staff and freelance journalists who are passionate about telling science stories that are true, important and compelling. Our editors and reporters are often experts in their fields, which means they understand the nuances of big discoveries and can untangle the breakthroughs from the hype. With a subscription, you are also supporting rigorous fact-checking to ensure the words we publish are precise and accurate. And you’re supporting original illustrations, graphics and photos that bring you closer to an advanced laboratory, an ice sheet in Antarctica or a space mission in orbit. You’re helping us craft other types of high-quality journalism as well: Our newsletters are carefully written, edited and curated by staffers you have or will come to know and love. Our Science Quickly podcast is based on original reporting, collaboration with editors and scientists and exacting production.
Subscriptions keep this engine running so we can continue to deliver thoughtful, rigorous and independent science journalism to you. In an era of viral misinformation, this work is crucial. If you value what we do, I hope you’ll consider joining us as a subscriber
