Antibiotics are medicines produced by various species of living organisms used to treat the growth of infection or diseases caused by bacteria because sometimes your immune system is not able to activate itself quickly enough to outpace the reproductive rate of a certain bacteria, or the bacteria is producing a toxin so quickly that it will cause permanent damage before the immune system can eliminate the bacteria. 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.