Vocal indicators of psychoactive drug effects were investigated in two experiments with normal subjects. In the first study antidepressants were administered, and in the second antihypertonics. Speech samples were collected at different stages during medication. Based on the known muscle-relaxing effect of these drugs, a decrease in average fundamental frequency (F0) and an increase in the proportion of spectral energy below 500 Hz (LFR) were expected. LFR showed the expected effect in both experiments. F0, on the other hand, only decreased in the first experiment, while in the second it showed a slight tendency to increase. The suitability of these two measures as indicators of emotional state is discussed.