Does Milk Make You More Congested When You Have a Cold? The Truth Behind the Myth

January 6, 2026 •

4 min read

For centuries, people have believed that drinking milk increases mucus production and worsens congestion during a cold. While the creamy texture of milk can create a temporary sensation of thicker phlegm in the mouth, scientific studies have repeatedly shown no link between dairy consumption and increased mucus secretion in the respiratory tract.

Quick Summary

Despite a widespread belief, research indicates that drinking milk does not increase mucus production or congestion during a cold. The feeling of thicker phlegm is a sensory perception caused by milk's creamy texture mixing with saliva. Certain individuals, particularly those with a diagnosed dairy sensitivity or lactose intolerance, may experience heightened symptoms, though this is not a general effect. Proper hydration and other home remedies are more effective for managing cold symptoms.

Key Points

The link is a myth: Scientific evidence does not support the claim that milk increases mucus production during a cold.
Sensory perception: The sensation of thicker phlegm after drinking milk is caused by its creamy texture mixing with saliva, not an increase in actual mucus.
Benefit, not harm: For most people, drinking milk provides beneficial hydration and nutrients that can support the body during an illness.
Hydration is key: Focusing on overall fluid intake, including water and broths, is a far more effective strategy for loosening congestion.
Lactose intolerance is different: Individuals with a confirmed lactose intolerance may experience gastrointestinal symptoms, but this is separate from respiratory mucus production.
Trust the science: Healthcare professionals often recommend dispelling the milk-and-mucus myth, as avoiding dairy offers no proven benefit for most cold sufferers.

Does milk make you more congested when you have a cold?

For generations, the belief that milk makes you more congested during a cold has been passed down, often cited as a reason to avoid dairy when sick. This idea has persisted since at least the 12th century and gained further traction in modern parenting manuals, despite a lack of supporting scientific evidence. Current medical research, however, paints a different picture, identifying this as a myth and clarifying the sensory experience that often misleads people.

The Science Behind the Myth: Texture, Not Production

So, if milk doesn't increase mucus production, why do so many people feel that it does? The answer lies in the unique sensory properties of milk. Milk is an emulsion of fat and water. When it mixes with saliva in the mouth and throat, it can form aggregates that temporarily increase the perceived thickness and coating sensation. This sensation can be mistaken for an increase in mucus, especially when a person is already experiencing a stuffy nose or post-nasal drip from a cold. In a double-blind study where participants were given either cow's milk or a soy-based placebo drink, those who believed milk caused mucus reported similar sensations of a coated throat and thicker saliva with both beverages. This suggests that the belief itself, rather than the dairy product, influences the perception of symptoms.

Scientific Studies on Milk and Mucus

Numerous studies have been conducted to investigate the link between milk intake and mucus secretion, with consistent results that refute the long-held myth. Researchers have challenged volunteers with the common cold virus and monitored their dairy consumption and mucus production, finding no statistically significant association.

A 1990 study: In a trial with adult volunteers infected with rhinovirus (a common cold virus), researchers found no correlation between milk intake and symptoms of congestion or the measured weight of nasal secretions.
A 2005 study: Published in the Journal of the American College of Nutrition, this study concluded that milk consumption does not lead to increased mucus production or the occurrence of asthma.
A 2019 study: A review in Archives of Disease in Childhood emphasized the lack of evidence supporting the myth, stating that healthcare workers should firmly rebut the idea that milk increases mucus.

These findings reiterate that for most healthy individuals, dairy products do not worsen cold symptoms.

Who Should Be Cautious About Dairy?

While the milk-and-mucus myth is largely unfounded for the general population, there are specific instances where some individuals might want to be mindful of their dairy intake. These cases are generally related to underlying conditions, not a standard viral infection.

Lactose Intolerance: For those with lactose intolerance, consuming milk can lead to gastrointestinal symptoms such as bloating, gas, and diarrhea. While not directly linked to respiratory mucus, general discomfort can exacerbate the feeling of being unwell.
Dairy Allergies: A cow's milk allergy is an immune system response, and in rare cases, it can trigger respiratory issues like asthma-like symptoms or excess mucus production. This is distinct from the milk-and-mucus myth and is a legitimate medical concern for affected individuals.
Individual Sensitivity: Some people simply report a personal sensation of increased phlegm after consuming milk, and if this causes discomfort, avoiding dairy during a cold is a reasonable personal choice. It is important to distinguish this subjective experience from objective, measurable mucus overproduction.

Comparison Table: Fact vs. Myth


Aspect	The Myth	The Scientific Fact
Cause of Congestion	Milk directly increases the body's production of mucus, leading to more congestion.	Congestion is caused by inflammation from the viral infection, not by milk intake.
The “Thick Phlegm” Sensation	Milk makes existing phlegm thicker and stickier, making it harder to clear.	The creamy texture of milk creates a temporary feeling of a coated throat, which is a sensory illusion.
Impact on Cold Symptoms	Drinking milk worsens all aspects of a cold, making recovery slower and more uncomfortable.	Milk provides hydration and nutrients, which can be beneficial during a cold, especially if warm milk soothes a sore throat.
For Those Who Are Sensitive	Everyone who is sick should avoid dairy.	Only those with diagnosed dairy allergies or lactose intolerance should be cautious.
Recommended Action	Eliminate all dairy during a cold.	Drink milk if desired; focus on general hydration and rest.

Effective Cold Remedies (That Don't Involve Avoiding Milk)

Instead of worrying about milk, focus on proven strategies to alleviate cold symptoms.

Stay Hydrated: Drinking plenty of fluids like water, clear broths, and decaffeinated tea helps loosen mucus and prevent dehydration.
Rest: Giving your body adequate rest is crucial for helping your immune system fight off the virus.
Humidify the Air: A cool-mist vaporizer or a steamy shower can add moisture to the air, which helps soothe irritated nasal passages and ease congestion.
Use Saline Nasal Sprays: Over-the-counter saline sprays can effectively moisturize nasal passages and help clear stuffiness.
Gargle with Saltwater: A saltwater gargle can provide temporary relief for a sore throat.

Conclusion

The belief that milk makes you more congested when you have a cold is a long-standing but unfounded myth. Scientific evidence has consistently debunked this idea, showing that milk does not increase mucus production. The perceived feeling of thicker phlegm is a temporary sensory effect caused by milk's unique texture interacting with saliva. While those with a diagnosed dairy allergy or lactose intolerance may need to adjust their intake, the average person with a cold can safely consume dairy. The best course of action is to focus on proven cold remedies, such as staying hydrated and getting plenty of rest, rather than needlessly cutting out a nutritious food source. For most, a glass of milk won't worsen a cold, and warm milk may even provide a soothing effect for a sore throat.

For more information on nutrition myths and facts, consult reputable sources like the Mayo Clinic.

Frequently Asked Questions

The feeling of a coated throat is a temporary sensory perception caused by the creamy texture of milk. When milk mixes with saliva, it creates a thick emulsion that can be mistaken for excess mucus, especially when you are already dealing with a cold.

Yes, the idea that milk increases mucus is a long-standing myth, with origins dating back centuries. Modern scientific studies have consistently disproven this link, finding no correlation between dairy consumption and increased respiratory mucus.

For most people, drinking milk is perfectly safe and can even be beneficial when you have a cold. It provides important nutrients and hydration, and warm milk can be particularly soothing for a sore throat.

No, children do not need to avoid milk during a cold. Milk is an important source of calcium and other nutrients for children, and restricting it based on this myth is unnecessary and potentially detrimental to their nutrition.

The same principle applies to other dairy products. The sensation of thickness or stickiness is related to the texture and is not a sign of increased mucus production from consuming these foods.

Staying well-hydrated is the best strategy for dealing with congestion. Water, clear broths, and decaffeinated teas can help thin mucus and keep your body hydrated, aiding in your recovery.

If you have a diagnosed dairy allergy, you should avoid dairy products entirely to prevent an immune response. If you are lactose intolerant, dairy can cause gastrointestinal discomfort, and you may find it more comfortable to avoid it when sick, though it is not a congestion issue.