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Immune system

The complex system of organs, tissues, cells, and cell products such as mucus that protects the body from potentially harmful organisms or substances.

Infection

The condition which results from the invasion of the body by microorganisms such as viruses and bacteria. Excess production of phlegm and coughing can be symptoms of an infection.

Inflammation

The redness, swelling and pain in body tissue, such as the tonsils or larynx, that results from infection. Inflammation in the airways can lead to cough, nasal congestion and fever.

Influenza

Influenza, also known as flu, is a potentially serious and very contagious illness caused by influenza viruses that infect the respiratory system. It is characterised by cough, fever, a sore throat, head and body aches and nasal congestion. Professional medical assistance is required, especially for the infirm or elderly. See also: Vaccine

Inhale

To breath air into the lungs.