An Antimicrobial is an agent that kills microorganisms or inhibits their growth. Antimicrobial can either be natural (garlic, honey, ginger, etc), or synthetic (sulphonamides, cotrimoxazole, quinolones, etc). Subsequently, also include chemical substances used to preserve pharmaceuticals, food or other organic material. In short, Antimicrobial Preservatives prevent decomposition or fermentation by preventing the growth of microorganisms. Examples include: Methyl, ethyl, propyl and butyl Parabens and Sorbic acid. Antimicrobial Medicines can be grouped according to the microorganisms they primarily act against. For example, antibiotics are used against bacteria; anti-fungals are used against fungi; anti-viral against viruses, anti-cancer drugs, anti-malarials, anti-tuberculosis drugs, anti-leprotics, and anti-protozoals, etc (see: Wikipedia).