Purified botulinum A exotoxin was used to treat 9 adults with strabismus, 22 adults with incapacitating essential blepharospasm and 1 adult with "senile" spastic lower-eyelid entropion. Eight of the strabismus patients received one injection each into one horizontal extraocular muscle under electromyographic control in the outpatient clinic; the ninth patient received two injections. One week after the injection there was an 81% change on average in the angle of deviation. In the three patients followed up for 4 to 9 months the average change was 66%. For the patients with blepharospasm the toxin was injected into the orbicularis oculi. Relief of spasm lasted an average of 12 weeks after the first treatment and 15 weeks after the second. In the patient with spastic entropion the symptoms resolved with repeated injection of the lower-lid orbicularis. In all three groups the injections were well tolerated. The main complication was transient ptosis, which occurred in about 30% of the first two groups.