In an open clinical study the authors have verified the effectivity and tolerance of 7-metoxytacrine cholinergic agent (7-MEOTA) in a total consisting of 14 patients with schizophrenic or schizoaffective psychoses suffering from tardive dyskinesias in long-termed treatment with neuroleptics. In the whole group consisting of 14 patients the seven days' administration of the experimental preparation in a dose of 100-150 mg pro die was evaluated. The 7-MEOTA preparation was administered to 7 patients for 2 weeks. In the seven and fourteen days' administration a favourable effect of 7-MEOTA on tardive dyskinesias was observed. A fast onset of the efficiency as early as in the first days of the treatment was recorded. In final evaluation a minimal reduction of 50% of the intensity of the dyskinesias (using the AIMS scale) in 29% of the patients treated for a fortnight was found. The 7-MEOTA preparation was well tolerated, no undesirable marked side effects being observed. A transient increase of ALT was found in 1 patient only in the 2nd week of the treatment. In experimental treatment the maintenance neuroleptical therapy was not discontinued. An improvement of the dyskinesias overlasted in some patients as long as 2 month g after the discontinuation of the administration of 7-MEOTA preparation.