Neurophysiological and neurochemical studies have demonstrated that piracetam improves learning and memory both in animals and humans. In recent years it has been shown that when a subject is engaged in a motor perceptual task, some psychomotor functions are correlated with a consistent pattern of brain electrical activity. Given the relationship between the movement-related brain macropotentials (MRBMs) and the cognitive processes associated with them, we considered the MRBMs particularly suitable for the neurophysiological assessment of the efficacy of piracetam in man. The aim of this study was to test the acute and chronic effect of piracetam administration on the MRBMs in normal children during the performance of a motor perceptual task. The design was a triple-blind study, during which the subjects took either placebo or piracetam in random sequence, with a washout period of 3 weeks. The dose was 170 mg/kg for the acute treatment and 140 mg/kg/day for chronic treatment. No side-effects were reported by the children during or after acute or chronic treatment with piracetam. There was no statistically significant difference between placebo or piracetam treatment with regard to 'performance', which was already optimal at baseline, and to electromyographic activity. On the contrary, the MRBMs were significantly modified by treatment. In particular the Bereitschaftspotential was present as a positive shift during acute treatment with piracetam and increased after chronic treatment. Skilled performance positivity (SPP) amplitudes were significantly increased and SPP latency reduced by chronic treatment with piracetam. piracetam appears to act on the catecholaminergic and cholinergic systems via an increase of the inhibitory hyperpolarizing processes.