According to the American Society of Microbiology, antiseptics work by changing the pH of the environment of bacteria, making the environment inhabitable. Since microorganisms adapt to their environments, antiseptics have to work quickly to kill off the bacteria before it has a chance to adapt.
The body is able to naturally fight off most types of bacteria. In fact, it is exposure to bacteria that helps the body build up a resistance to it. Studies indicate that the use of antibiotics, antiseptics and other germ-killing products on children are a strong contributor to the development of allergies later on in life.
According to the Centers of Disease Control and Prevention, one of the largest concerns in the medical field is a group of microorganisms that build up a resistance to antiseptics and antibiotics. Due to the rapid rate of mutation and proliferation times, there is concern that a very small colony of bacteria that is resistant to antiseptics and antibiotic has the potential to become a large colony quickly. Bacteria such as this is likely to give rise to a new form of pathogen that possesses a natural resistance to modern medicine. This works much in the same way as a person only taking half of his antibiotics, giving rise to what scientists and doctors call super-bacteria, which have grown resistant to the antibiotics.