6 Things You Probably Didn't Know About Snot

Snot is slimy, and for most, it's gross and not pleasant. But, for all the reactions that slime can provoke — disgust, pleasure, or fascination — we depend on our slimy secretions. We have snot for a reason, and that slime can protect us from cells and surfaces. For some, watching slime can even provoke feelings of relaxation.

Here are five things about snot that you probably didn’t know.

Snot, commonly referred to as mucus, is a substance found in the nose and sinuses. It plays a crucial role in the respiratory system by trapping dust, germs, and other particles, preventing them from entering your lungs. Snot also helps to moisturize the nasal passages and protect the sensitive respiratory tract from irritation and infection.

Read More: Digging Into Nose Picking and Why We Are Guilty of It

The mucous membranes lining the nose, sinuses, and throat produce snot. It is slimy because it contains a special type of protein — mucins. Mucins impart some useful functions. Not only have mammals retained mucins from evolutionary predecessors but also, our new mucins are always evolving — in a phenomenon called convergent evolution.

If a regular protein gene is altered with sections of chains of sugar–protein molecules, called repeats, new functions are acquired. Repeats with a lot of proline, threonine, and serine transform a typical protein to a mucin because of the polypeptide structure that is formed. Sugars can easily attach to and branch off of these sites through glycosylation.

Read More: 4 Crazy Facts to Know About Your Nose

Snot is primarily made up of water, mucins, antibodies, enzymes, and salts. What we call “slimy” is the paradoxical property of viscoelasticity. Secretions with mucins — like snot (mucus) or spit (saliva) — are known for their oozing, slippery, and sticky feel. In technical terms, this is called viscoelasticity. Mucus and saliva can act as lubricants to facilitate movement and act as difficult-to-penetrate barriers to protect cells and surfaces.

Viscoelastic materials have an inherently dual nature — they behave like liquid and solids— and how they flow or resist flow depends on temperature, the rate of strain and time. For example, a viscoelastic material can flow like a fluid, stretch like an elastic into a thin strand, and at some point break as if it were a solid.

Thanks to the structure of mucins, with sections of protruding sugar branches, mucus adheres well to a lot of surfaces because different parts of the molecule chains have the ability to bind with electrically charged, neutral or even hydrophobic materials.

Read More: The Purpose of Mucus, the Body's Unsung Hero

In a study that investigated which emotions were associated with 21 different textures, researchers found that slime could provoke fear and disgust, but also, happiness and surprise.

Touch is an important way for humans to process the physical world. And the processing of physical sensations, whether felt on the skin, in the mouth or emotional perceptions, can get intertwined.

The feel of slime even elicits autonomic psychophysiological effects (which are subconscious changes in the body related to the person’s emotional state). In another study, slimes with similar characteristics to those of body fluids and foods altered sympathetic (fight or flight) and parasympathetic (rest and digest) activity.

Foods like oysters and escargot — animals known for their mucus secretions — or okras and seaweed — plants that produce soluble starches (which are essentially chains of sugar molecules) are disliked or enjoyed around the world because of their gooey texture.

Read More: Plants Sense Snail Slime to Avoid Becoming Supper

In certain people, the feel of a slimy substance evokes strong physiological changes, which is called an autonomous sensory meridian response (ASMR). Slime is often featured in ASMR videos — videos that are designed to evoke feelings of calm and relaxation. Anecdotally, those who have watched videos of slimy substances and felt the sensations describe them as oddly satisfying or oddly relaxing.

ASMR may also be similar to synesthesia — a condition where you can experience a sense through another, like color and sound, at the same time. But in the case of ASMR, we may be unable to keep the connections of sensory information received by the brain from an emotional response produced by the brain.

Read More: Relaxing ASMR Sounds are Harder to Re-Create Than You’d Think

For some situations, it’s not the emotional response that’s important, it’s the emotional connection that it represents. When infants observe who is willing to exchange slimy secretions with one another, they can understand who is part of their inner circle, according to a recent study.

Researchers watched infants in this study to see how they reacted — where they looked and for how long — to simulated scenarios. They found that when young children observe behaviors like kissing or sharing utensils between people, they recognize that it defines a close or intimate relationship.

Read More: What Is Slime Mold?

Young children also seemed to grasp the intricacies of social relationships — that a close relationship defined different obligations or expectations than friendship did. Children also seemed to understand that for a close relationship — like between siblings — one would respond to the other in distress but wouldn’t expect toy sharing to occur between them.

You probably wouldn’t expect snot to define these social boundaries, but as we’ve learned, it’s a slime with many qualities and functions.

Snot serves as a crucial defense mechanism in the nose, capturing particles and organisms to prevent them from reaching the lungs. While the color of snot is not typically used by doctors for primary diagnosis, it can provide insights into the health of your nasal passages and overall health, according to Raj Sindwani, a medical specialist, in an interview for the Cleveland Clinic.

Clear snot is normal and healthy. It's what your body produces on a regular basis to moisten the nasal passages and trap dust or other particles before they can enter your lungs. Clear mucus is a sign that your immune system is working as it should, and there are no significant issues. However, an increase in clear snot production could indicate an allergic reaction or the onset of a cold.

Yellow snot is usually a sign that your body is fighting off an infection, typically a cold or sinus infection. The yellow color comes from white blood cells that have rushed to the site to combat the infection. As these cells get used up, they can turn the mucus a yellowish hue. While it's a common symptom, if yellow snot is accompanied by severe pain or fever, it might be a good idea to consult a healthcare professional.

Green snot often indicates a more severe infection than yellow snot. The green color results from an enzyme called myeloperoxidase, which is found in certain white blood cells that fight off bacteria or viruses. Green snot can be a sign of a bacterial infection, a lingering cold, or a sinus infection. While not always a cause for alarm, persistent green snot, especially with other symptoms like pain or fever, may warrant medical attention.

Bloody snot can be alarming, but it often isn't a serious issue. It can be caused by dry nasal passages, which are more prone to bleeding, especially in low-humidity environments or during winter. Nose picking or nasal irritation, such as from blowing your nose too hard, can also cause blood to mix with snot. However, if bloody snot is frequent or accompanied by other symptoms, it's advisable to seek medical advice as it could be a sign of a more serious condition.

Read More: Coughs of Many Colors: When Should You Be Worried About Phlegm?

This article was originally published on Oct. 18, 2022 and has since been updated by the Discover staff.