What are antibiotics and how do they work?

What are antibiotics?

Antibiotics are medicines used to treat infections or diseases caused by bacteria (e.g. respiratory tract infections such as pneumonia and whooping cough).

Antibiotics are used for a range of other infections caused by bacteria, including urinary tract infections, skin infections and infected wounds.

Antibiotics have saved millions of lives since they were first introduced in the 1940s and 1950s. However, because they have been overused, many antibiotics are no longer effective against the bacteria they once killed. Find out what antibiotic resistance is and how it can affect you, and how you can help prevent it.

How do antibiotics work?

Antibiotics work by blocking vital processes in bacteria, killing the bacteria, or stopping them from multiplying. This helps the body's natural immune system to fight the bacterial infection.

Antibiotics differ in the types of bacteria they work against.

Antibiotics that affect a wide range of bacteria are called broad spectrum antibiotics (e.g. amoxycillin and gentamicin).

Antibiotics that affect only a few types of bacteria are called narrow spectrum antibiotics (e.g. penicillin).

Different types of antibiotics work in different ways. For example, penicillin destroys bacterial cell walls, while other antibiotics can affect the way the bacterial cell works.

Doctors choose an antibiotic according to the bacteria that usually cause a particular infection. Sometimes they do a test to identify the exact type of bacteria causing your infection and its sensitivity to particular antibiotics.