During the last seven years 65 patients with Gilles de la Tourette's syndrome have been treated. Pimozide was used as the preferred drug because of our experience of treating other hyperkinesias which indicated fewer side-effects than with haloperidol. Of the 65 patients with Gilles de la Tourette's syndrome, 59 were treated with pimozide alone or in combination with tetrabenazine or clonidine. The dose ranges of pimozide were 0.5-9 mg per day. Eighty-one percent experienced a good clinical response without side-effects. The side-effects seen in our patients were sedation, gain in weight, depression, pseudoparkinsonism and akathisia; acute dystonic reactions, blurred vision, slurred speech and xerostomia did not occur. No cases of tardive dyskinesia were seen.