Know your snot colour

As the winter days and nights catch you and your family in a web of seasonal colds and coughs, here's a little handy guide for you to know how is your immunity doing

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Ever wondered why the colour of your snot is different when you're sick? You're probably not the first person to ask this question. There are actually many reasons why your snot's colour changes when you're unwell. And the colour and consistency of nasal mucus can reveal intriguing details about your immune system, and how your body responds to illnesses.

Mucus is produced by the tissues lining our nasal passages. Often perceived as a mere nuisance, mucus serves a very important role. It acts as a protective barrier, trapping dust, bacteria, viruses and other irritants - preventing them from reaching the respiratory system's deeper parts. Enzymes such as lysozyme and lactoferrin that inhabit our nasal mucus also have antimicrobial properties. They break down bacterial cell walls and help to limit bacterial growth. This protective role makes mucus a critical line of defence - even when we're not unwell.

The continuous process of mucus production by the tissues lining our nasal passages exemplifies the body's natural defence mechanisms in action. When we get sick, mucus changes - becoming thicker, more abundant and sometimes colourful. These changes highlight your immune system's response.