Are Onions Good for Respiratory Infections? Facts and Home Remedies

For centuries, onions have been a staple in folk medicine for treating respiratory ailments, with anecdotal evidence suggesting they alleviate coughs and congestion. Modern research has explored these traditional claims, revealing that onions contain powerful compounds with anti-inflammatory, antioxidant, and antimicrobial properties that may support the body's immune response to respiratory infections. However, the key lies in understanding the science behind these claims and how to properly utilize their potential benefits.

Quick Summary

This article explores the scientific basis and traditional uses of onions for respiratory infections. It examines the roles of compounds like quercetin and sulfur compounds in providing anti-inflammatory, antioxidant, and antimicrobial support. Practical home remedies and a comparison of raw vs. cooked onions are included, alongside potential risks and when to see a doctor for persistent symptoms.

Key Points

• Immune System Support: Onions are rich in vitamins, minerals, and antioxidants like quercetin, which bolster the immune system to help fight off infections.

• Anti-inflammatory Properties: Quercetin in onions helps reduce inflammation in the respiratory tract, providing relief from swelling and irritation caused by infections.

• Natural Expectorant: The sulfur compounds in onions can help break down and expel mucus and phlegm, acting as a natural expectorant to relieve congestion.

• Traditional Remedies: Folk remedies like homemade onion and honey cough syrup leverage the antibacterial and soothing properties of these ingredients to ease symptoms.

• Quercetin's Antiviral Role: Scientific research shows quercetin can interfere with viral replication and block viral entry into host cells, supporting the body's fight against various viruses.

• Hydration and Nutrients: Drinking onion tea or broth helps with hydration and provides beneficial compounds, which is crucial during an illness.

• Potential Risks: Be aware of digestive side effects from raw onions and the ineffectiveness of unproven remedies like placing cut onions in a room to absorb germs.

The Science Behind Onions and Respiratory Health

Onions are more than just a flavorful kitchen staple; they are packed with potent phytochemicals and nutrients that can support overall health, including the respiratory system. The key to their therapeutic potential lies in several bioactive compounds.

Quercetin: A Powerful Antioxidant

One of the most notable compounds in onions, especially red onions, is quercetin, a flavonoid with strong antioxidant, anti-inflammatory, and antiviral properties. Quercetin works by inhibiting oxidative stress, which can damage cells and contribute to chronic diseases. For respiratory health, research indicates it can help modulate inflammatory responses and inhibit viral replication, particularly in lab studies involving viruses like rhinovirus and influenza. By calming inflammation in the airways and protecting against cellular damage, quercetin can assist the body in fighting off infections more effectively.

Sulfur Compounds: A Natural Expectorant

The characteristic pungent flavor and odor of onions come from their organosulfur compounds. These compounds have been shown to have antimicrobial and expectorant properties. As an expectorant, these sulfur compounds help loosen and expel mucus from the lungs and airways, providing relief from congestion associated with respiratory infections like colds and bronchitis. While the strong fumes from a cut onion can cause the eyes to water and temporarily loosen congestion, this is more of a temporary physical reaction than a deep healing process. However, when ingested, these compounds can offer more systemic support.

Vitamins and Minerals: Immune System Support

Beyond their unique compounds, onions are a good source of essential nutrients that bolster the immune system. They contain a notable amount of vitamin C, a powerful antioxidant vital for immune function. Onions also provide B vitamins and minerals like selenium and zinc, all of which contribute to the body's overall defense mechanisms against pathogens.

Traditional and Modern Uses for Respiratory Issues

For centuries, various cultures have used onions in different forms to treat respiratory ailments. These practices have given rise to several home remedies, some of which are now being supported by scientific understanding of the onion's properties.

• Onion Cough Syrup: A classic home remedy involves layering sliced onions with honey or sugar and letting the mixture sit for several hours. The honey draws out the onion's juices, creating a syrup believed to soothe sore throats, reduce coughing, and offer antibacterial benefits.
• Onion Tea: Steeping chopped onion in hot water and drinking the resulting infusion is another method. Adding lemon and honey can improve the flavor and provide additional vitamin C and antimicrobial benefits. This method can help hydrate the body and ease congestion.
• Consuming Cooked Onions: Incorporating cooked onions into broths and soups is a gentle and effective way to benefit from their anti-inflammatory properties while staying hydrated. Combining onions with garlic and other immune-boosting herbs creates a powerful, comforting meal.
• Inhaling Onion Vapors: Some folk remedies suggest placing a cut onion near a bed to clear congestion by inhaling its vapors. While there is no scientific proof that an onion can absorb germs from the air, the release of sulfur compounds may provide temporary relief for some individuals, though the effect is often minor and anecdotal.

Comparison: Raw vs. Cooked Onions

Feature	Raw Onions	Cooked Onions
Beneficial Compounds	Retains the maximum amount of organosulfur compounds, which are potent but also unstable.	Heat can break down some organosulfur compounds, but cooking can make quercetin and other antioxidants more bioavailable.
Digestive Tolerance	Can cause heartburn, bloating, and gas in sensitive individuals due to higher levels of fermentable fibers.	Milder and easier on the digestive system, suitable for those with sensitive stomachs.
Taste Profile	Pungent, sharp, and can be overpowering for some.	Sweet and mellow, which can make them easier to consume in larger quantities.
Best for	Quick, concentrated remedies like honey syrup or direct consumption for potent, immediate effects.	Daily consumption in soups, stews, and other dishes for long-term immune support and anti-inflammatory benefits.

Conclusion

While onions should not be considered a cure-all for respiratory infections, they offer significant benefits that can support the body's natural healing process. Their richness in antioxidants like quercetin provides anti-inflammatory and antiviral support, while their sulfur compounds act as natural expectorants to help clear congestion. Incorporating onions into a balanced diet through cooking or home remedies like honey syrup can be a helpful, natural way to support immune health during cold and flu season. However, these remedies are best used as complementary support and not as a replacement for medical advice, especially for severe or persistent infections. For serious symptoms or infections, consulting a healthcare provider remains the most important step. Adopting a holistic approach that includes nutrient-dense foods like onions can empower you to proactively support your respiratory well-being.

Potential Risks and Considerations

While generally safe for consumption, there are some potential side effects and considerations when using onions for respiratory infections:

• Digestive Issues: Raw onions contain certain fibers that can cause gas, bloating, and heartburn, especially for individuals with irritable bowel syndrome (IBS) or sensitive digestive systems.
• Allergies: Some people may have an onion allergy, which can trigger symptoms like nasal congestion, itchy eyes, and asthma.
• Unproven Folk Remedies: Placing cut onions in a room or a sock to absorb germs has no scientific basis and should not be relied upon to prevent or cure illness. Germs are spread through contact and airborne droplets, not absorbed by onions.
• Food Safety: Cut onions should be stored properly in a sealed container in the refrigerator to prevent bacterial growth and should not be left out for long periods.
• Infants and Toddlers: Honey should never be given to infants under one year old due to the risk of botulism. Always consult a pediatrician before administering any remedy to young children.

When to See a Doctor

While home remedies can provide symptomatic relief, it is essential to seek professional medical advice if you experience severe or persistent respiratory symptoms. Consult a doctor if you have:

• A high-grade fever
• Difficulty breathing or shortness of breath
• A cough that lasts more than three weeks
• Persistent chest pain
• Wheezing or difficulty swallowing
• Coughing up blood or bloody phlegm

Authoritative Outbound Link

For more information on the immune-boosting effects of quercetin, particularly in respiratory diseases, you can consult research articles from the National Institutes of Health.(https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9673223/)

References

Beneficial Effects of Daily Consumption of Garlic and Onion Extract on the Incidence of Respiratory Infections in the Elderly, MDPI, May 15 2023. A Little Onion Goes a Long Way to Boost Your Respiratory Health, Gills Onions, August 07 2023. Onion syrup for mucus buildup relief - Facebook, January 16 2025. The health benefits of onions: Healing properties abound, BBC Good Food, February 20 2020. (PDF) Antibacterial Effect of Onion - ResearchGate, ResearchGate, February 15 2018. How One Can Get Rid Of Cough And Cold With The Help Of Onion, Avni Kaul, April 14 2020. Can Onion Water Cure Colds or Flu? The Truth About the Latest Viral Trend, INTEGRIS Health, January 17 2023. Protective mechanism of quercetin and its derivatives in viral-induced respiratory illnesses: a comprehensive review, BMC Pharmacology and Toxicology, November 18 2022. Does Putting an Onion in Your Sock Stop a Cold or Flu?, Verywell Health, November 12 2024. Onions & Flu - National Onion Association, National Onion Association, January 18 2023. For those asking, this is really simple cough syrup. Finely chop ... - Facebook, Facebook, March 31 2024. Make a Natural Cough Syrup | BBC Gardeners World Magazine, BBC Gardeners' World Magazine, March 24 2019. Onion Benefits: Nutrients, Antioxidants, and More - Healthline, Healthline, May 20 2025. Health Benefits of Onions: Why You Need Them in Your Diet, Pachanga Produce, May 19 2025. Efficacy of Garlic and Onion against virus - ResearchGate, ResearchGate, September 21 2025. Home Treatments for Babies - WebMD, WebMD, September 01 2015. Can Onion Water Relieve Your Cold Symptoms? The Truth ... - Inspira Health Network, Inspira Health Network, January 31 2023. 10 Health Benefits of Onions - Spice World Inc, Spice World Inc, March 27 2024.

Frequently Asked Questions

How do onions help with a cough?

Onions help with a cough primarily due to their expectorant properties. The sulfur compounds they contain can help loosen and expel mucus from the respiratory tract, while the high antioxidant content helps soothe inflammation, easing irritation in the throat and airways.

Is it better to eat raw or cooked onions for respiratory issues?

Both raw and cooked onions have benefits, but for different reasons. Raw onions retain the highest concentration of volatile sulfur compounds, while cooking can make the antioxidant quercetin more bioavailable. If you can tolerate the strong flavor, raw onions offer a potent, concentrated dose. For those with sensitive stomachs, cooked onions in soups or broths are a gentler way to gain benefits.

Can onions act as a natural antibiotic?

Onions have been shown in laboratory studies to possess antibacterial properties, particularly against certain types of bacteria. The flavonoid quercetin is believed to damage bacterial cell walls and membranes. However, this is not a substitute for prescribed antibiotics, and medical advice should be sought for severe bacterial infections.

Does putting a cut onion in a room absorb germs?

No, the belief that a cut onion can absorb germs from the air is a debunked myth. Respiratory viruses and bacteria are spread through person-to-person contact and airborne droplets, not absorbed by an onion. While the fumes might temporarily relieve congestion, the method has no scientific basis.

What is onion syrup and how is it made?

Onion syrup is a traditional remedy for coughs and sore throats. To make it, you layer sliced onion with honey or sugar in a jar and let it sit for several hours. The honey extracts the onion's juices, creating a soothing syrup that can be taken by the spoonful.

Are there any risks to using onions for respiratory infections?

While generally safe, eating large amounts of raw onion can cause digestive issues like heartburn and gas in some people. Honey-based remedies are unsafe for infants under one year old due to the risk of botulism. Always consult a doctor for severe symptoms or persistent illness.

How long do homemade onion remedies last?

Homemade onion remedies, such as onion and honey syrup, should be used quickly and stored in the refrigerator. Most recipes recommend using the syrup within a day or two to ensure freshness and potency.