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The Myth of Milk and Mucus: Coughs, Colds, and Asthma

Photo by Stefan Kühn. CC-BY-SA licence.

Photo by Stefan Kühn. CC-BY-SA licence.

Does drinking milk cause you to produce more mucus and make conditions like coughs, colds, and asthma worse? Surprisingly, the answer is both yes and no—and the answer largely depends on whether you personally believe it does or not.

It seems to be well known that drinking milk will make you more "stuffed up." Drink milk when you have a cold, they say, and you’ll be blowing your nose all day and night. Worse, it’ll stop you getting rid of that chest infection that’s been plaguing you for weeks. And if you’ve ever suffered from asthma, forget it. Milk, for you, is definitely off the menu.

Milk Does Not Cause You to Produce More Mucus

Except that "they," whoever they are, are wrong. In a quite disgusting experiment conducted by the Department of Community Medicine at the University of Adelaide, Australia, researchers infected over 50 people with the common cold and then collected and weighed the snot of those people for the next 10 days.

Some of the subjects didn’t drink any milk for the duration of the experiment. Some of them drank more than 10 glasses of milk a day. Some didn’t believe in the theory that milk produces mucus; others believed it with a righteous passion.

But when the researchers gathered in all the data, they found that there was no difference. Drinking milk had zero effect on the quantity of mucus produced.

The Power of Belief: The Nocebo and Placebo Effects

The placebo effect is what happens when you believe a pill, potion, tincture, or snake oil will work. If someone believes that what they are taking (or doing) will help them recover from illness, there is a greater chance of them getting better.

The nocebo effect is the opposite. There is a rumour that one gentleman in the 1970s was told by his doctor that he had a terminal illness and had just a couple of months to live. He did indeed die within that time, but the autopsy showed no signs of disease, and it was eventually concluded that he had died because his doctor said he would. Possibly this is just a rumour—certainly I’ve been unable to find any reputable records that confirm the story—but I’ll be treating any doctorly advice with some scepticism nonetheless.

What the experiment above, with the milk and the common cold, did find was that a very small, statistically insignificant percentage of those people who believed in the theory coughed a bit more after they drank some milk.

It’s Not Asthma: It’s a Milk Allergy

So where did the belief come from, and why is it so common? Well, in a review of all the scientific studies on milk and mucus by the Allergy Department at the University Hospital of Zurich in Switzerland, it was found that in some people who have an allergy to cows’ milk, their symptoms after drinking milk were very similar to asthma.

Although lactose intolerance is fairly common, and especially the milder forms, having a true milk allergy is relatively rare. However, the symptoms of a mild allergy and an intolerance can possibly be remarkably similar. This does not mean that lactose intolerant people will experience asthma-like symptoms by drinking milk, but what it could mean is that people with a mild lactose intolerance may associate other symptoms with drinking milk, and thus have a more deep-rooted belief that milk causes mucus—and from the Australian experiment above, we know that simply having a belief in this can cause someone to cough more.

Does This Mean It’s All in Your Head?

No, certainly not. It is all a lot more complicated than that.

In people with a milk allergy (even a mild one), or for people who have a lactose intolerance, drinking milk will mean that the efforts of your immune system will be diverted to dealing with the problems that milk causes when you ingest it. This means that if your immune system is busy dealing with that problem, it won't be dealing with your cold—or at least not as well as it could—which might make your cold symptoms worse, or make your cold last longer.

But even just the non-physical aspects of drinking milk can cause problems for some people. Stress and depression cause your immune system to work less well. And conversely, relaxation and happiness cause your immune system to work better. And it doesn’t take a lot to upset your stress-happiness, and therefore your immune system balance. So if you have just drunk a glass of milk, and if you believe that it will make you feel worse—maybe because you have a mild lactose intolerance that you haven’t had checked out properly—there will be two stresses at work in your body: an upset digestion from drinking milk, and a belief that you did something that will make you feel worse. In response, your immune system will be just that bit less able to cope efficiently.

Image released into the wilds of the Public Domain by wolvenraider.

Image released into the wilds of the Public Domain by wolvenraider.

So What Are You Saying? Should I Drink Milk or Not?

Do you want to drink milk? Do you believe it will make you feel better or worse? Have you been tested for a milk allergy? Are you lactose intolerant?

Milk will not make you produce more mucus. However, for some people—lactose intolerant people—it can give you other symptoms that can make you feel a bit miserable and ill and thus lower your immune response and maybe lessen your ability to fight off infections. And for others, simply believing that milk causes mucus will make you cough. For anyone with a milk allergy, obviously dairy products should be avoided and you should talk to your doctor. But for most people, you can drink milk until... well, until the cows come home, and it won’t make a speck of difference to your cold or chest infection.

This content is accurate and true to the best of the author’s knowledge and does not substitute for diagnosis, prognosis, treatment, prescription, and/or dietary advice from a licensed health professional. Drugs, supplements, and natural remedies may have dangerous side effects. If pregnant or nursing, consult with a qualified provider on an individual basis. Seek immediate help if you are experiencing a medical emergency.


Rick Tufts on June 18, 2019:


Sheila on July 18, 2017:

Idiots wrote this. If you study 50 people with no sensitivity/allergy to milk, guess what? No symptoms. Duh!

I had a cough for almost 2 years, and was tested for every allergy possible with no results. Later I went off of milk products and guess what? The symptoms went away. I went back on milk, the symptoms returned.

Articles like this discourage people from doing the one thing that will help them. Then they go and pretend that it is a placebo effect. Why would I have symptoms for almost 2 years before suspecting that milk caused the symptoms? If I had believed that, I would've stopped the milk much sooner. This article is doing a great disservice to people who are only looking for relief. You should take it down.

Hendrika from Pretoria, South Africa on August 11, 2014:

Interesting. My son has a mild milk allergy, that started in his 40's, but it really is a drag. You do not realize all the places you will find dairy products in. Often in restaurants they say no but then there is some. Otherwise I also believe that milk has no influence on any illness, at least not as far as I am concerned.

Christine Rogers from Ohio on August 08, 2014:

This proves what my mom always told me wrong, good hub! very useful.

Chuck Bluestein from Morristown, AZ, USA on April 11, 2014:

At age 19 I told this woman that I had post nasal drip and lots of nasal problems including nasal headaches. She asked if I drank milk. I told her that I drank 8 glasses of milk a day. She said to try to not drink any milk and see how you feel. All the problems had gone away.

An adult cow weighs about 1,000 pounds while an adult goat weighs about 150 pounds. They know that goat's milk is much healthier for people that cow's milk. Here are 2 facts. The USDA says that goat's milk is healthier than cow's milk. More people in the world drink goat's milk than cow's milk. Of course human milk is the healthiest milk for humans.

cynsible on February 08, 2014:

My doctor tested me for a dairy allergy that came back negative. However, I can drink a glass of organic skim cow's milk and will sneeze twenty times and then suffer post nasal drip the next day. My grandparents had a dairy farm and I love milk. I do not have the typical lactose (gastro) response that others suffer. My mother and niece have stopped having asthma attacks since stopping dairy. When I convinced my best friend to give dairy a break she called me the next day with tears of joy to be free of the 'tissue in the sleeve' at only 28 years old. After reading this article, I tend to think that there must be some component of the milk that is being overlooked. I can go with the busy immune system theory as my Mom and I both have Hashimoto's Disease. I was also relieved of chronic itchy ears upon stopping dairy, but did not know that to be a symptom until much later, which make me think it is not all the power of suggestion. Recently, I was chatting with a friend about how six months ago I couldn't eat bananas without sneezing and now I can. She asked if I was allergic to ragweed. Of course I am. I am allergic to all weeds. She told me that bananas grown in an area where the growth of ragweed was in season were in fact cross contaminated with ragweed. So I will continue to enjoy bananas until I can't. This makes me wonder if it is something in the diet of the cow who made the milk. Whatever it is, avoiding dairy food works for a cure for now. I can also sometimes cure a headache with a coke and a candy I say, whatever works, works. Thanks for the discussion on this! ;-)

Carrie Lee Night from Northeast United States on October 20, 2013:

Voted up and interesting. Thank you for taking the time to write this hub. Have a wonderful week :)

Clinton on March 31, 2013:

Basically it's all in your subconcious...

Gerry on November 24, 2012:

All my early life I had on going colds. Now that I am 63 years old my colds have gone away but for years my sinuses continually produce lots of phlem and I have an incessant post nasal drip. Anything that I cough up is thick and often green. My doctor, bless his heart, told me to add Vicks to a bowl of hot, hot water and breathe in the steam twice a day. Also, to drink lots of water. Well things improved somewhat but early one morning 4 days ago I woke up with a typical heavy cough that felt like the phlem was going to cut off my air supply. If anyone has ever choked on food you know the feeling. I was seriously freaked out and concerned and once again tried to self diagnose why I was having such phlem. The night before I had this frightful experience I had had a bowl of yogurt and decided after reading that milk products can cause excessive phlem that I was going to stop having any dairy. Amazingly with continued steaming my nose and throat are absolutely clear. The phlem and post nasal drip have vanished. That was 5 days ago and for once in my life I'm no longer suffering with congestion and can breath clearly through my nose. As far as I'm concerned this is a miracle and I'd recommend to others with sinus issues to do likewise and go off all milk products. Hopefully you'll have the successful results I've had.

Redberry Sky (author) on July 18, 2012:

Cheers, Dinkan :) I've read that too about raw milk, and I've considered ordering it from a very responsible farm quite near where I live that doesn't use pasteurisation, but raw milk can harbour TB and other nasty diseases, so I always wonder if the risk is really worth it. I have read some really good research on the issue, though, so perhaps one day soon I might try it :)

dinkan53 from India on July 18, 2012:

I read in an article that, researchers found that raw milk can give protective effect against asthma and allergies because of some helpful proteins and these proteins will be destroyed while boiling. Anyway thanks for clearing the myth of milk and mucus. Very informative, rated as useful and shared with my followers.

Redberry Sky (author) on July 04, 2012:

Tamron – yes, milk always makes me feel better too when I’ve got the sniffles, especially in a nice hot chocolate before bed :)

Minnetonka Twin – cookies? Absolutely! Gotta keep your strength up when you’re feeling poorly!

Cheers, livingpah 2004, it’s nice to know we can all enjoy milk without the myths stuffing us up :)

Thanks Molometer, hope you’re both feeling better; the rain really has been awesomely persistent so far this summer in our green and pleasant land hasn’t it?

Tammyfrost – yes, milk just doesn’t seem to agree with quite a lot of people. Vive la difference :)

Tammy Winters from Oregon on July 04, 2012:

I have never been much of a milk drinker because I seem to get sick to my stomach whenever I do drink it with cereal. Thanks for your tips.

Micheal from United Kingdom on July 03, 2012:

I actually just said this last night. With the constant rain we have been having we have both got 'bunged' chests up with mucus (lovely) and have been coughing our lungs up. (sweet) lol

I am so glad to know that the myth of milk is just that, a myth.

Well researched hub with great information.

Voted up interesting and very useful. Sharing. Let's dispel this myth.

Milli from USA on July 02, 2012:

I am glad to know about the myth of milk and mucous. Now I can drink milk. Great information and voted up!

Linda Rogers from Minnesota on June 28, 2012:

Gross research but very informative. I was told by a chiropractor that milk is terrible for people with asthma or other lung conditions. I blew off his advice and continue to drink milk. I love milk! Here are some food pairings that have to include milk: Milk and Chocolate Chip Cookies, Milk with a Candy Bar. Thanks for that useful hub.

tamron on June 23, 2012:

What an awesome article! When I saw the title" The Myth of Milk and Mucus: Coughs, Colds and Asthma" I had to read it because I always felt better drinking milk during a flu or cold. I felt like it coated my stomach and brought the mucus up. I knew it had to be a myth!

Redberry Sky (author) on June 20, 2012:

Hi Crystal, I know, doctors' advice changes so quickly depending on the latest research, and conflicting advice is everywhere! I tend to read the research results, but then go with what my body tells me is good or bad :)

Redberry Sky (author) on June 20, 2012:

Hi aethelthryth, I've often thought about switching to raw milk, I've read that it is supposed to have a lot of health benefits. Interesting theory on raw v. pasteurised - I'll have to look into trying some if I can find a dairy farmer that produces raw milk.

Redberry Sky (author) on June 20, 2012:

That's interesting, Theresa, I didn't know about fat intolerance causing problems, and it's also interesting to know that for some people with asthma, milk has no adverse effects - health is so complicated! :)

Redberry Sky (author) on June 20, 2012:

Thanks, prospectboy :) I don't *think* it should make a cold last longer, prospectboy, but who knows how much medical research will be debunked again in a few years' time!? Important to go with whatever works for us, after all, once upon a time they thought leeches cured everything, and now hospitals use maggots on gangrene! :)

Bradrick H. from Texas on June 20, 2012:

I've always heard that it wasn't good to drink milk when you are sick. I never knew about the milk apparently producing more mucus thing. That's definitely interesting. I personally like drinking milk so much, that I often ignored people when they told me I shouldn't drink milk when I have a cold. Maybe that's why the last cold I had lasted so long. Interesting indeed. Great information and great hub. Voted up and shared on Twitter.

Teresa Coppens from Ontario, Canada on June 20, 2012:

I never believed the myths. I have a high fat intolerance so milk sometimes makes my stomach feel quesy or gassy if it is above 1%. Otherwise, no ill affects and I do have asthma. Great article and voted up!

aethelthryth from American Southwest on June 20, 2012:

Just as I always suspected. I love milk, and always wondered about this, because I never noticed any mucus effect on me. Of course, I grew up drinking raw milk, which tastes much better, and it wouldn't have surprised me if raw milk and homogenized milk worked differently with producing mucus.

Crystal Tatum from Georgia on June 20, 2012:

I've always heard that milk makes you produce more mucus, and have even been advised by doctors not to drink it when battling sinus difficulties. Goodness, it's hard to know what to believe! Very informative hub.

Redberry Sky (author) on June 20, 2012:

From what Chris Hugh said, I think it's the 'gunky' feeling we get in our mouth that makes us think milk makes us more stuffed up - like an autosuggestion thing. I would have gone with the idea myself until I read the researchon it.

Amber Lynn on June 20, 2012:

I was one of those people that swore milk made you produce more phlegm until I read this hub,a nd now I am seriously thinking that the milk may not be it! Thanks for the great information, nice job!

Redberry Sky (author) on June 20, 2012:

Cheers, Cheryl. It's good to know that we can talk ourselves into being healthy! :)

cherylvanhoorn from Sydney on June 20, 2012:

As a Nurse I agree with you one hundred percent. It was funny the amount of times that a placebo would work. Conversely the power of belief is massive.

Terrye Toombs from Somewhere between Heaven and Hell without a road map. on June 20, 2012:

Very interesting hub, great work, Redberry! :)

Redberry Sky (author) on June 20, 2012:

Cheers Daughter of Maat :) I agree that we should put our own experiences above lab results - whatever works for you is the best for you.

Redberry Sky (author) on June 20, 2012:

Wise choice jeannieinabottle (great name!) - I wouldn't be able to eat or drink *anything* if I listened to every rumour and half-whisper! Cheers :)

Mel Flagg COA OSC from Rural Central Florida on June 20, 2012:

Great hub, although I know milk caused more mucous for me, because when I switched to almond milk it all went away! What do doctors know anyway? A little biochemistry, pashaw.... :D Voted up and had to share it.

Redberry Sky (author) on June 20, 2012:

Ah, yes, Joan - the notorious 'wind allergy'. I get that too. You'd think they could come up with a tablet for that - like with hayfever. Or maybe fix it so we get better weather :)

Redberry Sky (author) on June 20, 2012:

That's a really good point, Chris - I know what you mean, milk always makes my mouth and throat feel all coated and, like you say, gunked up.

Doctors can be great, but the evidence of your own eyes should come before anyone else's opinion - even (maybe especially, since it's our lives we're talking about) medical opinion.

Joan Veronica Robertson from Concepcion, Chile on June 20, 2012:

Very interesting Hub! I have eliminated milk with flavors from my diet, and my digestion is much better, but all the rest is just the same! I have drunk milk all my life, and now I stick to just pure milk, or as pure as modern production makes it! My sinus "alergy" hasn't changed at all, it fluctuates depending on whether I'm out in the wind! Not with whether I drink milk. Voted up, useful, awesome (very good research) and interesting.

Jeannie Marie from Baltimore, MD on June 20, 2012:

This is really interesting. I've always heard that about milk, too. I just tend to ignore the warnings though. Milk always helps me feel better and even helps settle my stomach. What I really want to is, where did doctors find 50 people willing to get sick and then have their snot measured? Ewww! I sure hope they paid them a lot. Great hub and voted up!

Chris Hugh on June 20, 2012:

My voice teachers all said that milk gunks up your throat. I've noticee that it gunks up my throat as soon as I drink it, so it can't be that it's creating more mucus if the effect is immediate.

As far as the doctor who cursed his patient to death...yes, it happens. That's exactly how curses work. If the victim believes it and the shaman ("doctor" here) believes it and if the society supports the belief, the person can indeed die.

Redberry Sky (author) on June 18, 2012:

Thanks so much for sharing that, meditatio, it's great to hear that these things work in real life as well as in the lab - I'm as sceptical of researchers as I am of doctors, so I like to hear when people have found that some things really work for them.

meditatio from North Vancouver on June 18, 2012:

Until I moved to Canada, I had never heard about not drinking milk when you're sick. I keep saying so to my husband, but he insists on not having any milk when he's sick, "because it increases phlegm".

Now, I have a milk intolerance, and I *cured* my asthma when I removed milk from my diet. I think he's got a milk intolerance too :)

Thanks for posting about that myth !