In a double-blind, placebo-controlled study the encephalotropic and psychotropic properties of both orally and intravenously administered doses of vinconate (OC 340)--a new vincamine analogue--were studied in 10 elderly subjects in their sixties by means of quantitative EEG and psychometric analyses. They received at weekly intervals randomized single oral doses of placebo, 40 mg, 80 mg and 160 mg vinconate orally as well as placebo and 30 mg vinconate intravenously. EEG recordings and the monitoring of blood pressure, heart rate and side effects were carried out at the hours 0, 1, 2, 4 and 6. Psychometric tests were performed at the hours 0, 2, 4 and 6. Computer-assisted spectral analysis of the EEG showed a significant CNS effect of vinconate as compared with placebo characterized by a decrease of delta activity, increase of alpha and specifically of alpha-adjacent slow beta activity as well as an acceleration of the centroid of the total activity. Such changes were described previously by us after several other antihypoxidotics and are indicative of improvement in vigilance in the sense of Head (Br. J. Psychol., 14, 125-147). The encephalotropic effect was most pronounced after 160 mg vinconate p.o. followed by 80 mg and 40 mg vinconate orally, which timewise could be observed best in the 6th hour after drug administration. Changes after the i.v. injection of vinconate peaked as early as the 2nd hour post-drug. Psychometric investigations demonstrated only small psychotropic effects, which rarely reached the level of statistical significance as compared with placebo. Generally, the orally administered vinconate induced a trend towards an improvement of psychomotor activity, complex reaction and cognitive function as well as a significant improvement in attention and concentration, while the von Zerssen score increased as compared with placebo. 30 mg vinconate i.v., however, induced an improvement in mood as well as a shortening of reaction time and activation in the after-effect as compared with placebo in addition to a trend towards improvement in psychomotor activity, complex reaction and Pauli test. Evaluation of pulse rate, blood pressure and side effects showed a good tolerance of the drug. The findings are discussed.