Antibiotics <ref name="Antibiotics"/> , also called antibacterials, are a type of antimicrobial drug used in the treatment and prevention of bacterial infections. They may either kill or inhibit the growth of bacteria. A limited number of antibiotics also possess antiprotozoal activity. Antibiotics are not effective against viruses such as the common cold or influenza; drugs which inhibit viruses are termed antiviral [[Antiviral drugs ]] or antivirals rather than antibiotics.
Sometimes the term antibiotic (which means "opposing life") is used to refer to any substance used against microbes,synonymous with antimicrobial. Some sources distinguish between antibacterial and antibiotic; antibacterials are used in soaps and disinfectants, while antibiotics are used as medicine.