Is it good to eat onions during a cough?

December 19, 2025 •

4 min read

For centuries, onions have been used in traditional folk medicine to alleviate symptoms of respiratory ailments, including coughs. These pungent vegetables contain beneficial compounds that may provide relief, but is it good to eat onions during a cough? The answer lies in their specific properties and how they are consumed.

Quick Summary

Onions contain compounds like quercetin and sulfur that have anti-inflammatory and expectorant properties. These can help soothe a cough and clear mucus, especially when used in homemade remedies like onion and honey syrup. However, scientific evidence is limited, and chronic or severe coughs require medical attention.

Key Points

Natural Anti-Inflammatory: Onions contain the antioxidant quercetin, which can help reduce inflammation in the airways and soothe throat irritation associated with a cough.
Expectorant Properties: The organosulfur compounds in onions can help thin and loosen mucus, making it easier to expel phlegm from the respiratory tract during a wet cough.
Soothing Onion-Honey Syrup: Combining onions with honey, a natural cough suppressant, creates a soothing syrup that can relieve minor coughs and sore throats.
Limited Scientific Evidence: While historically used, strong clinical evidence specifically for onions curing coughs is lacking, and severe or chronic coughs need proper medical care.
Not a Cure-all: Traditional folk remedies, such as placing raw onions in a room, are not scientifically supported; the benefits come from ingesting the compounds.
Caution for Infants: Honey should never be given to children under one year old due to the risk of infant botulism, even in onion-honey remedies.

The Scientific Basis of Onions for Cough Relief

Onions (Allium cepa) contain several bioactive compounds that are believed to contribute to their therapeutic properties, which have been used for thousands of years. Two of the most notable are quercetin and organosulfur compounds, which have been studied for their potential health benefits, particularly in relation to respiratory health.

Quercetin: A Powerful Antioxidant

Quercetin is a flavonoid that functions as a powerful antioxidant and anti-inflammatory agent. Studies have shown that quercetin can help reduce inflammation, which is often a contributing factor to coughs and other respiratory irritation. By inhibiting pro-inflammatory molecules, quercetin may help calm irritated airways, which could, in turn, help alleviate a persistent cough. Red and yellow onions generally contain higher levels of quercetin than white varieties.

Organosulfur Compounds: Natural Expectorants

Onions also contain organosulfur compounds, which are responsible for their strong, pungent smell and taste. These compounds have been shown to act as natural expectorants, meaning they can help thin and loosen mucus in the respiratory tract. This process makes it easier to cough up and expel phlegm, helping to clear congested airways and providing relief from chest congestion associated with a wet cough.

Popular Onion-Based Remedies for Coughs

While eating raw onions can offer some benefits, many traditional remedies involve preparing them in specific ways to create a more palatable and concentrated form for cough relief.

Homemade Honey-Onion Syrup

One of the most popular home remedies is a simple onion and honey syrup. Honey is a well-documented natural cough suppressant that coats the throat and soothes irritation. When combined with the expectorant and anti-inflammatory properties of onions, it creates a soothing and effective concoction.

Recipe for Onion-Honey Syrup:

Ingredients: 1 medium-sized onion (yellow or red), 4-5 tablespoons of raw honey.
Instructions:
1. Peel and dice the onion.
2. In a glass jar, create alternating layers of diced onion and raw honey.
3. Cover the jar tightly and let it sit for at least 8-12 hours, or overnight, at room temperature.
4. The onion will release its juice, which mixes with the honey to form a syrup.
5. Strain the liquid and store it in a clean container in the refrigerator for up to 3 days.
6. Take 1 teaspoon every few hours to soothe a sore throat and reduce coughing.

Onion Tea

For those who prefer a warm beverage, onion tea can be a comforting option. Simmering chopped onion in water extracts the beneficial compounds into a liquid that can be sipped.

Recipe for Onion Tea:

Ingredients: 1 chopped onion, 2 cups of water.
Instructions:
1. Bring the water to a boil in a small saucepan.
2. Add the chopped onion and simmer for 15-20 minutes.
3. Strain the liquid into a mug.
4. Add lemon and honey to taste for added relief and flavor.

Raw Onion Consumption

Eating raw onion, perhaps added to salads or other dishes, can deliver a direct dose of its beneficial compounds. However, this is not always a pleasant experience for everyone and may cause digestive upset in some individuals.

Comparison: Onions vs. Standard Cough Remedies

To understand the role of onions in treating a cough, it's helpful to compare their approach to that of over-the-counter (OTC) medications.


Feature	Onion-Based Remedies	Standard OTC Cough Syrup
Primary Mechanism	Soothes throat, thins mucus, offers anti-inflammatory and antimicrobial support.	Suppresses cough reflex or acts as an expectorant (guaifenesin).
Active Compounds	Natural compounds like quercetin and organosulfur.	Chemical compounds like dextromethorphan (DM) or guaifenesin.
Scientific Evidence	Largely anecdotal or based on in-vitro/animal studies; clinical trials are limited.	Extensive clinical trials and regulatory approval.
Safety & Side Effects	Generally safe for most healthy adults, but can cause digestive upset; honey should not be given to children under one year.	Can have side effects such as drowsiness or dizziness and interact with other medications.
Suitability	Best for mild, acute coughs and as a supplementary treatment.	Necessary for severe or chronic coughs, or when advised by a doctor.

Limitations and Considerations

While onions offer several potential benefits, it is important to understand their limitations. They should not be considered a cure for severe or chronic coughs, which require proper medical evaluation. Furthermore, common folk remedies like placing sliced onions in a room to absorb illness have no scientific backing. The therapeutic effects are primarily linked to consuming or ingesting the compounds. Anyone with underlying health conditions should consult a doctor before relying on home remedies alone.

Conclusion: Making an Informed Decision

In summary, consuming onions can be beneficial during a cough due to their natural anti-inflammatory and expectorant properties. Homemade remedies like onion-honey syrup or onion tea can provide soothing relief for mild, acute coughs, especially when paired with honey's proven ability to coat and calm an irritated throat. However, it is crucial to manage expectations, as the scientific evidence for these effects is not as robust as for conventional medicine. For persistent, severe, or chronic coughs, relying on the guidance of a healthcare professional is always the safest and most effective course of action.

Frequently Asked Questions

While raw onions contain beneficial compounds that may provide mild relief, they cannot cure a cough. A persistent cough is a symptom that can indicate various issues and may require professional medical attention.

To make onion and honey cough syrup, dice an onion and layer it in a jar with raw honey. Let it infuse for 8-12 hours, then strain the liquid. The resulting syrup can be taken by the teaspoon for relief.

No, placing an onion in a sock has no scientific evidence to support its effectiveness for treating a cough or other illnesses. The theory is based on historical folklore, not modern medical understanding.

You should not give honey to children under one year of age due to the risk of infant botulism. For children over one, onion and honey syrup can be used in smaller doses, but always consult a pediatrician first.

Red and yellow onions tend to have higher levels of the antioxidant quercetin compared to white onions, which may offer slightly more anti-inflammatory benefits for respiratory health.

Onions have expectorant properties, which means they can help thin and loosen mucus in the chest, making it easier to cough up and clear congestion, especially when ingested.

For cough relief, it is most common to consume onions in the form of a prepared remedy, such as onion and honey syrup or onion tea. These methods make it easier to ingest the beneficial compounds.