Onions on a supermarket shelf.
Onions are best left for cooking rather than attaching to body parts in efforts to fight a fever. (Dan Peled/AAP IMAGES)

Onions on feet for fever claim leaves a bad smell

Georgina Jerums May 4, 2022

Putting sliced onion on the bottom of your feet can help to relieve a fever.


False. Experts say there is no scientific evidence the remedy reduces fever.

While the humble onion can be a culinary hero, a Facebook post claims the pungent root vegetable is a cure for fever when slipped in your socks.

However, experts told AAP FactCheck there is no therapeutic effect from the home remedy, which will result in smelly feet and a pesky laundry challenge.

The post lists a number of onion health tips, leading with “For Coughs, Cold and Fever”, stating “Onion effectively lowers high temperatures” and advising people to “slice a piece of onion and place it on the socks to lower body temperature”.

A screenshot of the Facebook post
 A Facebook post says placing sliced onion on the sole of your foot will reduce a fever. 

But the claim is scientifically unproven, experts say.

Onions do have anti-inflammatory and antioxidant properties when eaten, but don’t have any fever-reducing effect when applied to feet.

The claim is not new as detailed on the US National Onion Association’s website. The theory dates back to the bubonic plague of the 1500s when sliced raw onion placed around the house was mistakenly thought to rid a home of the plague, which was assumed to be airborne but was in fact caused by fleas.

Similarly, the purported fever remedy goes back to the ancient Chinese medicinal practice of foot reflexology, where feet are deemed to be access points to internal organs.

Joe Schwarcz, director of McGill University’s Office for Science and Society, told AAP FactCheck there’s no evidence to show onions have a therapeutic effect to treat illness.

Dr Schwarcz says placing onions in socks may have to do with reflexology, which applies pressure to the sole of the foot to treat disease.

“The theory, a scientifically bankrupt one, is that points on the sole are connected to various organs in the body, the workings of which benefit from stimulating specific areas on the sole of the foot,” he said in an email.

“Onion proponents claim various compounds in onions can be absorbed through these areas and ‘purify the blood’ and ‘detoxify organs’. They buttress these arguments with studies showing that onions have some antibacterial properties. That can be shown in some cell cultures in the laboratory, but this has no practical application.”

There can be health benefits from eating onions, including absorbing flavanoids, which help fight inflammatory diseases, getting a hit of Vitamin C to boost the immune system, as well as compounds that help ward off cardiovascular disease.

Paul Prenzler, associate professor in chemistry at Charles Sturt University, says medicinal plants are used to treat fever in traditional Chinese medicine, but the claim onions on feet can work “seems highly unlikely”.

Polyphenolic antioxidants get released in the gut when onions are consumed,” he told AAP FactCheck in an email.

“However, just putting onion on the skin is very unlikely to transfer enough polyphenolic antioxidants to the body to have any effect.”

Medical experts say the best way to self-treat a fever is usually by taking a paracetamol or ibuprofen, and drinking plenty of fluids. It’s recommended people consult a medical professional if high body temperatures persist.

Dr Schwarcz says the healthiest place for onions is not on your feet but in your mouth.

“For now, I will restrict myself to putting onions in the frying pan instead of in my socks.”

The Verdict

The claim that placing a slice of raw onion on the soles of your feet and putting on socks will reduce a fever is false. Experts told AAP FactCheck there is no therapeutic effect from the home remedy and the claim is not supported by medical evidence.

False – The claim is inaccurate.

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