Why is your snot green, yellow or "other" in colour?

First of all, EWWWW! Gross question Kellie, but an interesting one that is relevant to anyone with a shnozz. Exit Voldemort.

A quick Google search returned results which included a web article from The Naked Scientist, encouragingly called - What do Snot and Wasabi have in common?

But you didn't come here to my blog to have to wade through the scientific facts of snot - that's my privilege. Plus, I own the appropriate rubber-based protective gear to do so hygienically.

I must warn you however, that I am not a doctor, nor do I play one on TV. So you can trust me.

From what I can deduce, there are 2 types of mucous gunk in the nose/mouth/throat region.

1. Nasal mucous (snot) - produced at the back of the nose

2. Phlegm - produced in the rest of the respiratory tract (the breathing bits of your throat and chest)

Both mucosae (mucuses) are water-based liquids (never a gas, sometimes a solid when dried and needs picking) containing carbohydrates, salt and importantly for our question, protein cells.

The normal colour of mucous is clear to white, but depending on the health of the person, it can be brown from the tar in cigarettes, pink/red/rust/black from blood, or yellow/green - the colour of interest to us.

Mucous is always present in the nose and throat as it keeps the tissue in the area moist and acts as a barrier to protect the lungs from foreign bodies like pollen, dust or East Timorese boat people. Actually, I may have gotten confused on that one with all the tabs I have open at the same time.

Anyway, once it has done its job, we either hock up the mucus, or mostly, it goes down into our stomachs to meet up with acids to kill any infection-causing bacteria.

So why the skittles-like range of colours? Mucous, like Matt Preston, is very absorbent and easily soaks up other liquids and solids like tears, blood and tar, which explains all the colours (EXCEPT yellow and green!).

Let's look at enzymes! These are protein cells that increase a chemical reaction.

The two funky hues in question, are created by the cells in the mucous itself rushing to the site of the threat (bacteria, viruses etc.) and overpowering it with powerful antiseptic chemicals. This potent immune response results in the mucous cells being killed alongside the foreign cells and build up of these dead cells causes the yellow colour (think of the colour of dry/dead skin). The green colour is created by the iron in co-enzymes (helpers to the enzymes) that are needed to produce the antiseptic chemicals.

The more serious the infection; the more enzymes needed; the greener your snot.

The iron in the co-enzymes is the same iron that gives wasabi its green colour. Real wasabi that is, not the stuff we have here in Australia (or indeed anywhere out of Japan really) which is horseradish paste dyed with blue and yellow colour.

And there is your answer! Well, an answer.

It sounds right, and so long as you deliver the information here in an authoritative manner, I doubt anyone is going to question it. And if they do, just flick a nice green booger ball at their back.

The wise sage Jim Carrey once said "Is that tempura in your belly or are you just happy sashimi?"

By Monique Kowalczyk

So what do you want to know?
MoniqueWillKnow@gmail.com

*Disclaimer*
Please don't go basing your PhD Thesis on anything I write here.
The information I provide comes with no guarantee of accuracy, and I'm just as likely to provide the most entertaining answer, as I am the factually correct answer.