The natural history and response to different treatments were assessed in 31 consecutive patients with blepharospasm (BS) and/or oromandibular dystonia (OMD). The mean age at onset was 52.4 years and there was a female preponderance of 2.5 to 1. Ocular symptoms preceded the onset of blepharospasm in more than 50% of the affected patients, whereas psychiatric and dental problems prior to the onset of focal dystonia were found in 10% and 13% of the cases respectively. Dystonia elsewhere, mainly in the craniocervical area, was found in 23% of patients and appeared to follow a somatotopic progression. The first 2-3 years of history were crucial for the spread of dystonia to other face and body parts. When OMD was the first symptom, a lower tendency of dystonia to progress elsewhere was observed. A putative cause was found in 14% of patients who showed clinical and radiographic evidence of basal ganglia or rostral brainstem-diencephalon lesions. The response to different drugs was inconsistent although transient improvement was induced by haloperidol in 6 patients, by L-Dopa plus deprenyl in 3 patients, by trihexyphenidyl in 2 patients and by clonazepam in 2 patients. One, apparently spontaneous, remission was observed. Botulinum A toxin was injected in the orbicularis oculi of 8 patients affected by BS: moderate to marked improvement lasting 5 to 30 weeks (mean 14.5 weeks) was achieved in all cases; transient ptosis, lasting 1 to 3 weeks, occurred in 3 cases.