The influence of celiprolol on the symptoms of tardive dyskinesia was compared with placebo in a randomized double blind study. 17 female patients were treated with a single daily dose of 200 mg celiprolol and 18 female patients received placebo for a period of 3 months. All patients got additional neuroleptic treatment. Celiprolol produced a small decrease in heart rate and systolic blood pressure, but had no influence on the diastolic blood pressure. The effects of celiprolol on the symptoms of tardive dyskinesia were similar to those of the placebo; in both groups improvements and deteriorations were observed. One patient of the celiprolol group became symptom free. Two cases of collapse occurred after 10 weeks of treatment with celiprolol. In one case collapse was associated with diarrhoea, in the other case the patient had preexisting hypotensive circulatory dysregulation. Sporadic reports about the effect of propranolol in patients with tardive dyskinesia might reflect the normal progress of the disease or the effect might depend on the different pharmacological profile of propranolol.