Botulinum toxin type A stands alongside digitalis, atropine, and paclitaxel as natural compounds that, although first noted for their toxic properties, are now routinely used as medicines. The recorded history of botulinum neurotoxins dates back to human encounters with improperly stored food, which caused the sickness known as botulism when ingested. In the early 1800s, the German physician Kerner provided one of the earliest descriptions of food poisoning caused by botulism that followed ingestion of smoked sausages1. In the late 1800s, Professor van Ermengem, a Belgian microbiologist, identified botulinum neurotoxin as the cause of botulism in a group of Belgian musicians who had eaten inappropriately prepared sausages.