Six patients with moderate or severe tardive dyskinesia participated in a 14-day double-blind crossover comparison of placebo with 50 g/day of lecithin. There were no side effects, and Abnormal Involuntary Movement Scale (AIMS) ratings of videotaped examinations indicated significant improvement in the dyskinesias of all subjects during the lecithin trial, even with concomitant administration of a constant dose of neuroleptic medication to five patients.