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Debunked: No, leaving onions around your home won't 'catch' the coronavirus

False claims on Facebook suggest that onions are able to absorb germs.

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A POST HAS been shared on Facebook claiming that onions can be used to “catch the cold & flu germs” and stave off Covid-19. 

Apparently inspired by a practice in China, the claim is not true

Onions are neither effective ways to prevent the coronavirus entering your home nor do they catch cold and flu germs. 

Here is is in full:


This particular post has been shared nearly 2,000 times on Facebook. 

The post advises that people should “half an onion and leave it out around your house. Its [sic] supposed to catch the cold & flu germs”. 

“Apparently a house in China was doing this & everyone else around had the Corona virus bar this one house that had the onions sitting in each room cut open. When the onion was tested it was full of the virus.”

Onions – like garlic – have been attributed with infection and virus-fighting qualities in recent weeks as fears grow about Covid-19. 

The evidence

Myths about onions were around long before the world had heard of coronavirus. As highlighted in‘s coronavirus newsletter, some can be found in the Dú archives, which digitised The Schools’ Collection - an effort by the Irish government that tasked schoolchildren with recording folklore from their family and neighbours back in the 1930s.

More recently, myths have spread widely on Facebook. 

In 2015, a Facebook post claimed that a family had survived the Spanish Flu in 1919 by putting an unpeeled onion in rooms around the house, while the idea that placing an onion next to your bed will stop you getting the flu has long been a popular myth. 

But the claim isn’t true. Onions do not absorb bacteria or viruses. 

Both colds and the flu are caused by viruses, but again an onion isn’t going to be effective in fighting a virus. As we’ve all been told in recent weeks by the HSE, the coronavirus is spread in sneeze or cough droplets – typically being transferred on hands, objects and surfaces. 

As a sign of common this claim it, is has been debunked repeatedly down through the years. In 2015, fact-checking site Snopes wrote that there was no evidence to back up the claim:

No scientific studies back it, and common sense rules it out: cold and flu viruses are spread by contact, not by their nasty microbes floating loosely in the air where the almighty onion can supposedly seek out and destroy them.

Back in 2009, the Wall Street Journal similarly pointed to the fact the claim had no basis in fact:

Biologists say it’s highly implausible that onions could attract flu virus as a bug zapper traps flies. Viruses require a living host to replicate and can’t propel themselves out of a body and across a room.

More recently, the Australian Associated Press spoke to a molecular nutritionist who also rejected the claim.

“Stop and think about how dangerous onions would be to eat if that happened,” she said.

And writing specifically about bacteria, Joe Schwarcz, the Director of McGill University’s Office for Science and Society in Canada, wrote in 2017 that “onions are not especially prone to bacterial contamination. In fact, quite the opposite. Onions feature a variety of sulphur compounds that have antibacterial activity”. 

“The terminology that onions are ‘bacterial magnets’ makes no sense. No food attracts bacteria, although of course some are more likely to support bacterial multiplication or viral contamination once infected.  Like any food, poor handling can cause problems,” he wrote.

In other versions of this claim, it’s said that onions, if left next to a sick person, will turn black – a sign that they have absorbed the virus or bacteria.

Once again, this is incorrect. Any onion left out will eventually turn black as cells start to break down and it starts to rot. 

And while the World Health Organisation recognises some of the general health benefits of onions, it does not suggest that onions are capable of absorbing or warding off viruses. 

So if you are worried about the coronavirus, by all means eat onions – but leaving them around your house will not protect you. 

With reporting by Nicky Ryan

Misinfo Graphic 3030 Onion V2


There is a lot of false news and scaremongering  being spread in Ireland at the moment about coronavirus. Here are some practical ways for you to assess whether the messages that you’re seeing – especially on WhatsApp – are true or not. 


Look at where it’s coming from. Is it someone you know? Do they have a source for the information (e.g. the HSE website) or are they just saying that the information comes from someone they know? A lot of the false news being spread right now is from people claiming that messages are from ‘a friend’ of theirs. Have a look yourself – do a quick Google search and see if the information is being reported elsewhere. 

Secondly, get the whole story, not just a headline. A lot of these messages have got vague information (“all the doctors at this hospital are panicking”) and don’t mention specific details. This is often – but not always a sign – that it may not be accurate. 

Finally, see how you feel after reading it. A lot of these false messages are designed to make people feel panicked. They’re deliberately manipulating your feelings to make you more likely to share it. If you feel panicked after reading something, check it out and see if it really is true.’s FactCheck is a signatory to the International Fact-Checking Network’s Code of Principles. You can read it here. For information on how FactCheck works, what the verdicts mean, and how you can take part, check out our Reader’s Guide here. You can read about the team of editors and reporters who work on the factchecks here.

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