Botulinum toxin is a naturally occurring protein produced by the bacterium Clostridium botulinum. In 2002 it became FDA approved to treat facial furrows. There are seven distinct serologic types of botulinum toxins lettered A to G. There are two type A botulinum toxins widely available in the US, Botox(Allergen) and Dysport(Medicis).

A new botulinum A toxin named Xeomin (Merz Pharmaceuticals) was more recently FDA approved.