Viral infection of the mucous membrane of the nose. There are many viruses that can cause a cold, which explains why someone can have several colds a year, each being caused by a different virus. Children up to the age of 10 catch colds more frequently because their resistance to infection is still developing. The first symptoms are a runny nose, sneezing fits, red eyes and a tired, listless feeling. Breathing is impaired by the red, swollen mucous membrane, and the patient tends to breathe through the mouth, causing throat complaints such as hoarseness, a dry feeling in the throat, slight pain and coughing, and the lymph nodes in the neck are often tender. The nasal mucous membrane is readily susceptible to bacterial attack in this condition, and when they are involved in the infection the nasal mucus becomes a thick, yellowish-green secretion. After this the swollen membrane subsides, and breathing through the nose is easier again. The mucus is ‘nice and loose’. Usually a cold does not last for longer than seven days. If it persists for longer, the sinuses, throat and middle ear are often inflamed as well, and a doctor should be consulted. The early symptoms of a cold can also be the first signs of various children’s illnesses such as measles, chickenpox and scarlet fever. Influenza is also a possibility. There are several useful household remedies for controlling the most troublesome symptom, the blocked nose. To reduce the swelling of the mucous membrane several drops of a salt solution which one can make oneself (a pinch of cooking salt in a cup of water) can be dropped into both nostrils. Moistening the inhaled air relieves discomfort in the nose and pharynx. This can be done in the shower or by inhaling vapour from a bowl of hot water, possibly with added menthol drops, although this is best avoided with young children because there is a danger of breathing difficulties. If these remedies are not sufficient, nose drops to narrow the blood vessels can be applied, but after their effect wears off the vessels dilate again, causing renewed blockage of the nose (which means that drops have to be used again and again with increasing frequency). Nose drops must not be used for more than a week at a time in order to avoid damaging the mucous membrane.