Antibiotics are powerful medicines that fight certain infections and can save lives when used properly. Antibiotics either stop bacteria from reproducing or destroy them.
Before bacteria can multiply and cause symptoms, the body's immune system can usually kill them. Our white blood cells attack harmful bacteria and, even if symptoms do occur, our immune system can usually cope and fight off the infection.
There are occasions, however, when it is all too much, and some help is needed; this is where antibiotics are useful.
The first antibiotic was penicillin. Such penicillin-related antibiotics as ampicillin, amoxicillin, and benzylpenicillin are widely used today to treat a variety of infections - these antibiotics have been around for a long time.
There are several types of modern antibiotics, and they are only available with a doctor's prescription in most countries.
An antibiotic is given for the treatment of an infection caused by bacteria. It is not effective against viruses.
If you have an infection, it is important to know whether it is caused by bacteria or a virus.
Most upper respiratory tract infections, such as the common cold and sore throats are caused by viruses - antibiotics do not work against these viruses.
If antibiotics are overused or used incorrectly, there is a risk that the bacteria will become resistant - the antibiotic becomes less effective against that type of bacterium.
A broad-spectrum antibiotic can be used to treat a wide range of infections. A narrow-spectrum antibiotic is only effective against a few types of bacteria. Some antibiotics attack aerobic bacteria, while others work against anaerobic bacteria. Aerobic bacteria need oxygen, anaerobic bacteria do not.