Botulinum neurotoxins work by locally blocking the nevre impulses which control muscle movement.

Because of its ease of use, predictable results, and outstanding safety profile, Botulinum Type A neurotoxin complex (marketed by Allergan)  has become a popular and valuable treatment for a number of medical conditions, including cerebral palsy, migraine, excessive sweating, wry neck, back and facial spasms, as well as for the treatment of facial wrinkles.

When injected into muscle tissue, a flaccid paralyis results after about 3 days, and this paralysis can last any where from 3 to 8 months.