Antibiotics are medicines used to treat infections or diseases caused by bacteria (e.g. pneumonia, urinary tract infections, and infected wounds).

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

Antibiotics have saved millions of lives since they were first introduced in the 1940s and 1950s. However, because they have been overused and misused, many antibiotics are no longer effective against the bacteria they once killed (this is called antibiotic resistance).