Antibiotics are chemicals that help your body to fight diseases caused by bacteria and fungi. They are manufactured naturally by some microbes in order to protect themselves, but are now made synthetically. Different antibiotics work in different ways : Some stop bacteria reproducing by preventing the formation of cell walls, while others prevent them from absorbing nutrients. Antibiotics have no effect on viruses.
Broad-Spectrum antibiotics work against many bacteria and those work against specific micro organisms called selective antibiotics.
Overuse of antibiotics in human medicine and in animal feed has led some bacteria to mutate in to forms that are resistant such as strains of tuberculosis and the so called super-bugs.
See also : How does the immune system work?
