Tardive dyskinesia is an insidious and debilitating extrapyramidal side effect of neuroleptic drug treatment. Recent research has suggested that lecithin has been effective in treating tardive dyskinesia. Lecithin's effects were evaluated under double-blind placebo controlled conditions. Treatment conditions included a placebo control group, a lecithin treatment group, and a no-treatment control group. Subjects in the lecithin group received 60 gms/day of lecithin (33 gms of phosphatidylcholine) . Subjects in the placebo group received a similar mixture which contained no lecithin. Subjects received mixtures for 9-11 days. Treatment effectiveness was determined by subjective, objective, and global evaluations. All subjects were evaluated 3 to 4 days prior to treatment and following 9 to 11 days of treatment.