Putting an onion in your socks is an old natural remedy for colds that you may see posted on social media during the cold and flu season. The theory is that onions can absorb bacteria and viruses and, by doing so, can draw germs and toxins out of a sick person or even the air.
To date, there is no evidence to support this claim, and the National Onion Association confirms there is no scientific proof that "a cut raw onion can absorb germs or rids the air of toxins and poisons."
Verywell / Laura Porter
Origins of the Remedy
The onion cold remedy, which involves placing sliced onion in the bottom of your socks while asleep, has origins in both medieval healing and traditional Chinese medicine (TCM).
Medieval Origins
According to the National Onion Association, the idea that onions can prevent transmittable diseases dates back to the 1500s. During the bubonic plague, cut onions were placed around homes to keep people from contracting the deadly illness.
At the time, it was believed that illnesses were spread through the air as clouds of disease known as miasma (derived from the ancient Greek word for "pollution"). Miasma was supposed to be something you could smell, and onions, with their distinctive smell, were thought to absorb miasma and provide protection.
In medieval Italy, the term "miasma" gave rise to the word malaria, which translates to "bad air."
In more recent history, people hoped onions would provide protection against the 1918 Spanish flu pandemic. In one anecdote, a doctor was said to have ordered his patients to place cut onions in their homes. He claimed the practice kept them healthy while those who did not use the remedy became ill.
Traditional Chinese Medicine
Others contend that the remedy is founded on principles of traditional Chinese medicine. In TCM, the body is said to have 12 major access points known as meridians that form the pathways to each organ in the body. Six of the 12 meridians pass through the feet.
Although these foot meridians are often dormant (mostly because we cover our feet with shoes), their stimulation is thought to deliver health benefits, including improved immunity. It is a principle that drives the practice of foot reflexology.
Some people contend that onions have a stimulatory effect as they are regarded as a "warming food" in TCM, counteracting the cold and dampness that weakens the immune system. There are few, if any, studies to support this claim.
Why Onions in Socks Don't Work for Cold and Flu Prevention
Some of the claims about onions are loosely based on fact. For example, onions do not provide the ideal environment for viruses to multiply or survive. With a pH balance of 5.4 to 5.8, onions have mildly acidic properties inhospitable to many germs. Adenoviruses, for example, the most common causes of colds, thrive in a more neutral environment (around 7.2 pH).
This does not mean onions have strong antiviral or antimicrobial properties; they do not. To effectively kill adenoviruses and similar respiratory viruses, you need an alkaline solution like bleach with a pH of 11 to 13.
There is also no evidence that onions have any absorption properties specific to viruses, whether in the body or in the air. While onions do have mild antibacterial properties, colds are caused by viruses, not bacteria.
How Colds Are Cured
Colds are curbed by the body's own immune defense. These include antibodies that instigate and coordinate the immune response, white blood cells that target and attack the virus, and inflammation which triggers heat and helps move immune cells closer to the site of the infection.
There is no evidence that onions can draw the virus out of the body or that drawing the viruses to the foot has any benefits in healing colds.
Onion Use in Chinese Medicine
Even within the construct of TCM, the stimulation of meridians in the foot is mainly achieved through needling (acupuncture) and pressure (acupressure).
Moreover, the topical use of onions (Cong Bai) to ease cold symptoms is traditionally delivered as a paste applied to the chest, back, soles, palms, and back of the knees rather than the foot.
Home Remedies for Cold and Flu That Actually Work
Other home remedies can be effective at easing cold and flu symptoms. Some of these include the following:
- Tea with honey and lemon can help suppress your cough.
- Ginger can reduce nausea and may have antiviral properties.
- There is limited evidence that a saltwater gargle may help prevent viral cold and flu infections.
Other Health Benefits of Onions
While there is no scientific proof that onions can help treat or prevent colds, onions can be an important part of a healthy, balanced diet to better support your overall immune health. Some health benefits of onions include the following:
- Onions are low in calories and sugar and contain no fat. Three medium green onions provide all the vitamin K you need on a daily basis, supporting bone health and potentially reducing the risk of osteoporosis.
- Green onions are a great source of vitamin A and magnesium which support a strong immune defense and are rich in antioxidants like vitamin C that protect cells from damage caused by unstable molecules known as free radicals.
- Onions also contain one the highest concentrations of a plant-based compound called quercetin which studies have shown can boost the immune response in the form of increased white blood cell counts (particularly defensive ones called lymphocytes).
Summary
While some people believe that putting onions in socks can speed healing from a cold, there is no evidence that it works. Onions can support your immune health as part of a healthy diet, but they have no direct effect on cold viruses or cannot change the course of the infection in any way.