The term "the dirty dozen" refers to the 12 biological agents such as, for example, the anthrax bacillus or botulinum toxin that could be used as biological weapons. Even if their military use is considered unlikely physicians should be familiar with the problematic because these pathogens can also occur naturally or, respectively, cause disease as the consequence of a laboratory accident. It is of decisive importance to make the diagnosis as quickly as possible in order to limit any further spread of the disease.