“Drinking milk makes you produce more mucus.”

The idea that drinking milk makes you produce more mucus is a widespread belief, often resurfacing when people experience colds or allergies. This misconception has roots stretching back centuries, with some attributing its origin to the 12th-century physician Moses Maimonides, who, in his "Treatise on Asthma," advised against certain "phlegm-generating" foods, though his specific mention of milk was more about a "stuffing in the head". The myth gained significant traction in modern times, notably through Dr. Benjamin Spock's highly influential 1946 "Baby and Child Care" book, which suggested dairy might cause discomfort during upper respiratory infections.

Despite its enduring presence, scientific evidence consistently debunks any link between milk consumption and increased mucus production. Numerous studies and reviews have found no correlation between drinking milk and greater respiratory secretions, cough, or congestion, even in individuals intentionally exposed to the common cold virus. Experts emphasize that healthcare providers should actively challenge this myth, as milk provides essential nutrients, particularly for children, and avoiding it based on this false belief can lead to nutritional deficiencies.

The persistence of this myth largely stems from the sensory experience of drinking milk. When milk mixes with saliva, its creamy, velvety texture can create a temporary sensation of a "coating" in the throat or a feeling of "thicker saliva". This perception is often mistaken for an actual increase in mucus, even though objective measurements show no such rise. Studies have even revealed that individuals who already believe in the milk-mucus connection tend to report more respiratory symptoms after consuming milk, highlighting the powerful influence of perception over physiological reality.