Fifty-six injections of botulinum A toxin have been given to humans for correction of strabismus. The paralysis has been localized to the injected muscle in all cases. No systemic complications of any kind have ensued. The maximum time of paralysis occurs four to five days following the injection, and then gradually diminishes, depending on dose. The maximum correction of strabismus has been 40 prism diopters. The maximum follow-up after injection is six months. Injection of botulinum A toxin into extraocular muscle to weaken the muscle appears to be a practical adjunct or alternative to surgical correction.