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It is believed in many cultures that dairy products increase mucus and phlegm production. In India, Ayurvedic tradition dictates that curd should not be eaten at night. The concept of Viruddha Ahara explains that pairing certain antagonistic foods with each other, or the improper timing of eating certain foods can lead to overall health problems. Specifically, Krama Viruddha deals with eating curd at night and it is not recommended since it is believed to cause stiffness in joints and is especially bad for those with arthritis. Further, curd consumption at night is also linked with excess mucus production. 

(For more information, read our article on Ayurveda).

Similar ideas exist in traditional Chinese medicine as well as the writings of the 12th century doctor Moses Maimonides. In fact, influential parenting books have also advised against dairy products for children suffering from colds as it is believed to make them worse. 

Do these beliefs hold any water? There have been studies on dairy products - especially milk - relating to mucus production and they have shown there doesn’t appear to be a correlation between mucus production and dairy consumption. However, there is more to it than just that.

(For more information, read our article on Milk: Benefits and side effects)

What do studies say about dairy products leading to excess mucus production?

A bit of a disclaimer about the studies: they look primarily at milk and dairy products in general, and not at curd in particular. But because curd is derived from milk, some reasonable assumptions can be from them. 

A small study conducted in Australia divided participants into groups that were given a soy-based drink and cow milk. Some mint flavouring was added to the milks so that they couldn’t be distinguished from one another. It turned out that both groups - even the one that drank the soy drink - felt afterwards that their saliva felt thicker and that it was harder to swallow. Interestingly, those who believed that there was a link between milk and mucus production were more likely to say that mucus production had increased. 

In another study, a small group of participants were intentionally infected with the common cold and asked to live communally for a period of time and asked to drink milk throughout the study. Additionally, they were asked to collect their nasal secretions which were weighed afterwards to test if mucus secretions had actually increased. It turned out that there was no significant difference in the amount of secretions produced by any participants, even though those who believed that there is a link between milk intake and mucus production claimed to have more symptoms. 

What do these studies suggest?

Research seems to suggest that consuming dairy products does not increase mucus or phlegm production. However, those who believe it does may feel congested after taking them. The placebo effect can be quite strong and psychosomatic symptoms can also lead to a feeling of ill health.

To that extent, it might make sense for those who believe that milk products are bad during colds and before going to bed at night to stay off them. It can be empowering to follow advice that is comforting and it may make you feel better faster.  (To learn more, read our article on dairy products.)

There may be other reasons why people feel uncomfortable drinking milk, especially when they have a cold. Since milk is an emulsion, it can cause molecules to cluster together after it is mixed with saliva. This could give people a feeling of a full, congested throat and mucosal passages and they may believe they are producing more mucus.

Again, if you don’t like dairy products when you’re sick, it is perfectly acceptable to avoid them. However, it is also helpful to know that dairy products don’t increase mucus levels themselves and don’t adversely affect those from asthma and other respiratory diseases either. 

In conclusion, there should be no harm in having curd at night - just make sure you are following a balanced diet and space your meals regularly.


  1. CB Pinnock, et al. Relationship Between Milk Intake and Mucus Production in Adult Volunteers Challenged With rhinovirus-2 Am Rev Respir Dis . 1990 Feb;141(2):352-6. PMID: 2154152
  2. W K Arney, et al. The Milk Mucus Belief: Sensations Associated With the Belief and Characteristics of Believers Appetite. 1993 Feb;20(1):53-60. PMID: 8452377
  3. Allen Dozor, et al. Do You Believe Milk Makes Mucus? Arch Pediatr Adolesc Med. 2004;158(6):601-603.
  4. Frosh, et al. Effect of a Dairy Diet on Nasopharyngeal Mucus Secretion Laryngoscope . 2019 Jan;129(1):13-17. PMID: 30178886
  5. Bartley, et al. Does Milk Increase Mucus Production? Med Hypotheses . 2010 Apr;74(4):732-4. PMID: 19932941

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