Diethadione is the analeptic drug. The injection of diethadione is followed by a significant increase in tidal volume and decrease in breathing rate. Comparison of the alveolar ventilation obtained for each subject with and without administration of diethadione showed a significant increase after treatment. Diethadione may be successfully used in order to “activate” the EEG tracing of epileptic patients having a normal resting EEG pattern, as its administration is followed, in a high proportion of cases, by the appearance of specific alterations of convulsive type. The diethadione is absorbed also by oral route, and well tolerated, in active doses, by all the routes of administration; when the circulatory conditions are normal, it does not exert any significant influence over heart rate or blood pressure. It possess a strong simulant activity on the CNS and especially on the respiratory center. Diethadione appeared to be, on a weight basis, about 5 times as active as pentamethylenetetrazol.