Antibiotics have no effect on most infections which afflict the human body.
Viruses cause most of these infections and are completely unresponsive to antibiotics. Antibiotics were developed in the 1930's and 1940's to combat bacterial infections. At that time, infections such as pneumonia and tuberculosis were the major causes of death. Ability to treat these diseases and other bacterial infections was a major advance. Through the years, newer antibiotics have continuously been developed to fight a wider variety of infections.