Antibiotics are compounds that are used to treat infections caused by bacteria and fungi. They are very useful medicines and have saved the lives of many children with serious illnesses such as meningitis, pneumonia and septicaemia (‘blood poisoning’). Antibiotics can also be used to treat more common bacterial infections in children, including middle ear infections and skin infections.
Used correctly and when needed, antibiotics are among the most valuable medicines we have.
But only bacterial and fungal infections can be treated with antibiotics. They have no effect on viruses. Many infections, such as simple colds and some stomach upsets causing diarrhoea, are caused by viruses and can be destroyed only by the body's own defence mechanisms.
In many cases it is not possible to determine if an infection is due to a bacteria or a virus. This is particularly so with infections of the upper respiratory tract. These infections, which cause sore throats, coughing, runny noses and ear aches, are very common. Most children, especially when they first start mixing with lots of other children, will get about 5 to 10 of these infections a year.
The decision to recommend an antibiotic in these circumstances will depend on many factors, including the length and severity of the illness and the presence of other complicating factors. Tests may be necessary to find out which germ is causing the infection. Antibiotics can only treat infections that are caused by bacteria – they have no effect on viral infections.
There is a range of different antibiotics for doctors to choose from. Some are only effective against particular bacteria, while others, known as 'broad spectrum antibiotics', will kill a wide variety of different bacteria. The aim of treatment is always to try and match the right antibiotic to the germ most likely to be causing the infection.
When antibiotics are overused or not used properly, bacterial infections become harder to treat because of antibiotic resistance. Antibiotic resistance is when bacteria evolve and change so that antibiotics that were previously used against that type of bacteria are no longer effective.
That’s why it’s so important that children and adults only take antibiotics that have been prescribed for them, and to finish the entire course of antibiotics.
No medicine can be guaranteed to be free from side effects, and antibiotics are no exception. However, when side effects do occur they are usually mild. Diarrhoea is the most common. True allergy to antibiotics is uncommon and usually shows up as a rash.
Last Reviewed: 20 May 2013