Myobloc is the currently available commercial formulation of type B botulinum toxin. Released in the United States in 2000, it is approved by the Food and Drug Administration for the treatment of cervical dystonia. The most commonly used botulinum toxins, the type A toxins (Botox and Dysport), affect the SNAP-25 protein, whereas the type B toxin (Myobloc) affects vesicle-associated membrane protein, also known as synaptobrevin. Both type B and type A are antigenically distinct. This article explains the difference between Myobloc and type A toxins, reviews equivalency and other published studies, and describes practical uses for this product in facial aesthetics.