It is a substance that has the ability to kill bacteria, unicellular microorganisms or other organisms. Bactericides can come in the form of disinfectants, antiseptics, or antibiotics. To understand the use of bactericides, one must first understand what bacteria are. Bacteria have the ability to survive in almost all conditions on earth, be it warm and moist soil or radioactive waste that would not be hospitable to any other organism. Some bacteria can cause harm to humans, animals, or plants, while some may be necessary for the survival of plants, animals, and humans. Due to the fact that bacteria can survive in almost all conditions, it is often difficult to kill them. Therefore substances such as bactericides have been created to kill harmful bacteria while not harming the important good bacteria.

Often used as pesticides, these substances are usually made up of chlorine dioxide and help kill bacteria and odor. Bactericides are most effective when bacteria are killed in an enclosed area. Since they are non-toxic, they do not cause fires or explosions. These substances can even be installed in air conditioners to kill bacteria in the air. Often made of dry gas, these substances typically have less moisture compared to liquid sprays and are capable of killing bacteria in a short period of time without harming anything else.

Often available as an antiseptic, antibiotic, or disinfectant, the substance is used differently when it is in different forms. Disinfectants, unlike antiseptics or antibiotics, are not designed for use on the human body and are applied to non-living surfaces for the purpose of cleaning surfaces of any microorganisms that might be present on it and could be harmful when contact is made. A classic example of a disinfectant can be household dishwashing soap. These substances help disinfect any microorganisms present on the dishes and clean them for future use, providing a clean and hygienic surface. Aside from being available in the form of dishwashing soaps, bactericidal disinfectants can also be in the form of sprays or wipes that have been treated with bactericidal disinfectant soaps.