Folk remedy of placing raw onions on feet to cure illness lacks scientific evidence
Onions contain nutrients like vitamins and antioxidants, which can provide health benefits when eaten. Rigorous scientific studies are necessary to determine whether foods or practices possess curative properties. There is no known scientific evidence to support the practice of placing raw onions on or against the body to cure viral infections.
Incorrect: Onions contain many compounds with potentially beneficial effects for health when consumed. But the claim that placing them against the feet cures illnesses isn’t supported by any known mechanism based on scientific evidence.
A post shared on Facebook on 27 December 2023 claimed that chopped raw onions absorb toxins and purify air. The post also claimed that placing sliced raw onions against the feet can alleviate symptoms of sinus infections including cough. According to the claim, putting onions against the feet allows for the antibacterial benefits of the onion to be delivered directly into the bloodstream.
This claim isn’t new; variations regularly circulate during cold and flu season. We addressed the purported antiviral properties of onions in a previous claim and found that there is no scientific evidence to indicate that onions can cure illnesses. The same remedy has incorrectly been touted as a cure for cancer, malaria, and fever.
“Onions do not absorb bacteria,” according to Ruth MacDonald, a professor in the Department of Food Science and Human Nutrition at Iowa State University, who was interviewed on the subject in 2013:
“The idea that a vegetable would attract and suck into itself bacteria from the air is not even logical. The onion may turn black because it would eventually rot from both cell breakdown events and bacterial contamination if you left it out, not because it absorbs germs […] eating these vegetables provides antioxidants that can have health benefits, but they are unlikely to prevent or cure disease.”
The notion that chopped onions absorb toxins from the air dates back to plague pandemics in the Middle Ages, when people believed that disease was spread through the air. We now know that plague is an infectious disease and spreads via flea bites, inhaling infected droplets, or contact with infected tissues.
Onions possess health benefits, but don’t eliminate illness
Onions contain quercetin, a type of flavonoid that possesses antioxidative properties. They’re also rich in nutrients like calcium, potassium, and vitamin C. Still, while eating onions may have some health benefits when included as part of a balanced diet, we determined in a previous claim review that they cannot cure illnesses.
Nevertheless, the belief that chopped onions are a remedy for symptoms of viral infection persists. One 2023 survey on home remedies found that some participants believed “cut onion on the bedside table” can alleviate sore throat. However, this survey measured perceived effectiveness of home remedies rather than actual effectiveness.
Origins may be traced to another alternative medicine practice called reflexology
Placing raw onions against the feet appears to stem from principles of reflexology, a practice that massages pressure points—often in the feet—to alleviate symptoms of certain ailments. However, research on reflexology is typically of poor quality. One systematic review analyzing effectiveness of reflexology in palliative care found weak support for its benefits. Another systematic review found only low-quality evidence to support reflexology’s benefits for short-term pain and anxiety.
We also found no clear evidence confirming that reflexology can alleviate symptoms of viral infections. Using PubMed, a repository of scientific studies related to biology and health run by the U.S. National Library of Medicine, we searched the database for terms combining “reflexology” with variations on “virus”, and “illness”, which yielded no results.
- 1 – Sebo et al. (2023). Nonpharmacological home remedies for upper respiratory tract infections: a cross-sectional study of primary care patients in Switzerland and France. Family Practice.
- 2 – Candy et al. (2019). The effectiveness of aromatherapy, massage and reflexology in people with palliative care needs: A systematic review. Palliative Medicine.
- 3 – McCullough et al. (2014). The Physiological and Biochemical Outcomes Associated with a Reflexology Treatment: A Systematic Review. Evidence-based Complementary and Alternative Medicine.