Putting onions in your socks might sound odd, but some people swear that it’s a remedy for infections, such as the cold or flu.

According to the folk remedy, if you come down with a cold or the flu, all you have to do is slice a red or white onion into rounds, place them on the bottoms of your feet, and put on a pair of socks. Leave the socks on overnight as you sleep. In the morning, you’ll wake up cured of your illness.

This remedy may originate back to as early as the 1500s, according to the National Onion Association, when it was widely believed that placing raw, cut-up onion around your home could protect you from the bubonic plague. In those days, it was thought that infections were spread by miasma, or poisonous, noxious air. The miasma theory has since been replaced with the evidenced-based germ theory.

The general idea of putting onions in your socks may also stem from the ancient Chinese medicinal practice of foot reflexology. The nerves in the feet have been a focal point of Eastern medicine for thousands of years and are thought to act as access points to the internal organs.

Onions are rich in sulphuric compounds, which give them their pungent odor. According to the folklore, when placed on the feet, these compounds infiltrate the body. Then, they kill bacteria and viruses and purify the blood. Articles that make such claims also mention that placing onions around the room will rid the air of viruses, toxins, and chemicals.

Many studies have been done to assess the ancient Chinese practice of foot reflexology. A review of foot reflexology studies showed little evidence that foot reflexology is an effective practice for treating just about any medical condition. Some research also points to foot reflexology actually making infections worse. However, the overall quality of research studies on reflexology is generally very low.

Also, no studies have been done specifically to assess the benefit of putting onions in your socks or anywhere else on your body. While dozens of articles pasted all over the internet advocate the use of onions in your socks, they cite no experimental evidence. They rely only on claims and anecdotes.

No studies have been done to refute the claim of onions in the sock, either, but the mechanism by which onions in your socks is said to work is also questionable. Onions are slightly acidic, so they may have antibacterial results if rubbed onto things. According to Dr. Ruth MacDonald, professor in the Department of Food Science and Human Nutrition at Iowa State University, they “are much less effective than bleach or chemical antibiotics.” Viruses also require direct contact with a human host to spread. Therefore, an onion would not be able to draw in virus and absorb it.

Plenty of people around the internet swear by this remedy, but all signs point toward a case of a placebo effect.

Is it dangerous?

If you have the flu and are willing to try anything to bounce back, the good news is that putting onions in your socks is unlikely to hurt you. There have been no reports of harm from this practice.

If you want to help out your immune system, it may be a better idea to eat your onions rather than to stick them in your socks. It’s well known that eating onions, like most vegetables, is good for your health.

For example, onions are one of the richest sources of dietary flavonoids, which may decrease your risk of cancer and inflammatory diseases. Onions are also great source of vitamin C, a vitamin that plays an important role in immune function. Regular consumption of the organosulfur compounds found in onions and garlic may also prevent the development of cardiovascular disease, according to a 2010 review.

Putting onions in your socks won’t hurt you, but it probably won’t help, either. To get the full benefit from onions and to help your body recover from or prevent an illness, try eating them as part of a diet rich in fruits, vegetables, and whole grains. To improve your odds, wash your hands, avoid contact with sick people, and consider getting a flu shot. Also, make sure you get enough sleep.