Botulinum toxin: therapeutic agent to cosmetic enhancement to lethal biothreat.

The clinical effects of Clostridium botulinum and its extremely potent neurotoxin have been known for two centuries. The disease threat and the clinical uses are now well established. What's changed is the potential for botulinum neurotoxin to be used as a biological threat agent. The recent upsurge of illegal trafficking of reagent-grade toxin could, if bought in large enough quantities, be as serious a threat as other biothreat agents such as anthrax and smallpox, which have received much more attention. Fortunately, effective countermeasures are available.