Biological weapons are toxic materials produced from pathogenic organisms (usually microbes) or artificially manufactured toxic substances that are used to intentionally interfere with the biological processes of a host. These substances work to kill or incapacitate the host. They may be used to target living organisms such as humans, animals or vegetation.

There are a variety of microorganisms that can be used as biological weapons. Some of them include:

    * Bacillus anthracis: Anthrax
    * Clostridium botulinum: Botulism
    * Clostridium perfringens

Agents are commonly chosen because they are highly toxic, easily obtainable and inexpensive to produce, easily transferable from person to person, can be dispersed in aerosol form, or have no known vaccine. While it is possible to develop biological weapons from microbes, typically bacteria, finding a means of distributing the substances is difficult.

