The US National Library of Medicine1 says that antibiotics - powerful medicines that fight bacterial infections - can save lives when used properly. Antibiotics either stop bacteria from reproducing or kill them. "Your body's natural defenses can usually take it from there."
Before bacteria can multiply and cause symptoms, the body's immune system can usually destroy them. We have special white blood cells that attack harmful bacteria. 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.....from antibiotics.