In a double-blind, placebo-controlled study the encephalotropic and psychotropic properties of an acutely and 3-weeks subacutely administered novel drug Duxil® (consisting of 30 mg of the antihypoxic almitrine which increases the oxygenation of the arterial blood by specific action on the pulmonary exchange system and of 10 mg raubasine, which potentiates this effect via increase in peripheral circulation), were investigated in 12 elderly subjects in their 70s. Each subject had a treatment of 3 weeks with Duxil® and placebo (1 tablet b.i.d.) with an interval of 1 week in between (the order of drug sequence was randomized). EEG recordings, psychometric and psychophysiological tests as well as evaluation of pulse, blood pressure and side effects were carried out at 0, 2, 4, 6 and 8 h after the administration of one single dose on day 1 (acute effect), at the 0 h on day 21 (subacute effect) as well as at the 2, 4, 6, and 8 h after one additional superimposed dosage on day 21 (superimposed effect). Computer-assisted spectral analysis of the EEG demonstrated after single doses of two tablets of Duxil® only subtle changes in the resting EEG, while after subacute administration and even more so after one superimposed dosage highly significant changes were observed, which were characterized by an increase of total power, alpha and alpha-adjacent beta activity, decrease in fast beta activity, and by an augmentation of absolute and relative power of the dominant frequency. These findings are indicative of an improvement in vigilance. The latter was seen also at the behavioral level, as psychometric tests showed specifically in noopsychic variables a significant improvement in intellectual, mnestic and psychomotor performance after the novel antihypoxic compound, as compared with placebo. There were practically no changes in thymopsychic variables. Evaluation of psychophysiological variables and side effects showed extremely good tolerability of the drug.