White onions sit on a stall at a fruit store in Sydney on Wednesday, Sept. 11, 2013. (AAP Image/Paul Miller) NO ARCHIVING

Onion and sugar flu ‘remedy’ is more a recipe for bad teeth

AAP FactCheck July 21, 2021

The Statement

Multiple Facebook posts claim that a homemade medicine of raw onion and sugar can cure colds and flu in children – even newborns.

The recipe was posted to Facebook by a user in Australia along with the text: “Obviously there’s still a lot of people who don’t know about this simple and effective home remedy … it works better than any over the counter prescriptions that are out there and best of all your (sic) not giving your kids unknown chemicals or whatever poisons they put into meds these days”.

According to the post, the concoction is made by soaking sliced brown onions in sugar, before placing the mixture in the fridge overnight. “The next morning you will end up with liquid or onion juice on the plate. The liquid is what you take or give to your child,” it says.

At the time of writing, the July 6 post had been viewed more than 500,000 times and shared more than 3400 times. Other Facebook users in Australia and New Zealand have posted the same recipe, see here, here, and here.

The Facebook post
 The purported remedy is made by soaking sliced onions in sugar and placing the mix in the fridge. 

The Analysis

Dousing onions in sugar is a great way to make caramelised onions – but it’s not a good way to stop kids from getting colds and flu.

Paediatric respiratory health experts told AAP FactCheck that the mixture will do absolutely nothing to cure children of respiratory health problems and is more likely to result in a trip to the dentist.

Professor Anne Chang, the head of child health at the Menzies School of Health Research, told AAP FactCheck in an email that there is “no published scientific evidence whatsoever in reputable journals” to back up the claims made in the social media posts.

“Anything soaked in sugar is likely to be unhealthy,” she added.

Professor Sarath Ranganathan, a paediatric respiratory medicine from the Murdoch Children’s Research Institute, also told AAP FactCheck that the supposed remedy will do nothing to cure respiratory problems in children.

“There is no cure for colds, flu and bronchitis (or bronchiolitis),” he said in an email. “Occasionally wheezy children benefit with bronchodilators. Paracetamol can occasionally be given for high fever with distress (and) risk of influenza can be mitigated with seasonal vaccination.”

Prof Ranganathan said the most likely outcome from drinking sugary onion juice is that it would “rot the teeth”.

The myth that onions prevent colds and flu goes back many centuries. In the first century AD, Roman emperor Nero reportedly swore by onions as a cure for colds, while the claim that onions can treat influenza goes back to at least the 1500s, according to the US National Onion Association.

However, despite some anecdotal stories of success, the idea that mixing onions with sugar will prevent colds, flu and bronchitis is not supported by medical science.

Some studies have found that onion extracts can prevent respiratory disease in animals, such as this Japanese study showing that fructan (sugar molecules) extracted from Welsh onions could reduce influenza in mice. A 2019 study found red onion extract could help prevent lung lesions in chickens.

Onions also have nutritional benefits for humans, while some studies have found that their extracts could potentially improve wellbeing in a range of ways, such as reducing cholesterol, treating fungal diseases or lowering blood pressure. Other studies – see here, here, here, here and here – suggest onions may even help prevent some types of cancer, although further research is needed.

Despite these benefits, no credible research has concluded that onions or onion juice will stop humans from contracting a cold, influenza or bronchitis.

White onions sit on a stall at a store.
 Mixing onions with sugar to prevent colds and flu is not supported by medical science, experts say. 

The Verdict

There is no scientific basis for the post’s purported remedy, experts told AAP FactCheck. Studies have found onions may provide some health benefits to humans, however there is no evidence they will cure colds, flu or bronchitis.

False – Content has no basis in fact.

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