The present study has been performed to investigate the effect of i.v. administration of taurine on the electrical activity of the epileptogenic focus induced by penicillin applied to the right sensory motor cortex of adult rats. Taurine (100 mg/kg body weight) was administered 15, 30, 60, and 120 min before the application of penicillin. The EEG was unipolarly recorded by means of electrodes applied to the pia. Taurine caused a decrease of the frequency as well as the spike amplitude of epileptic discharge. The spread of epileptogenic foci to the opposite hemisphere was retarded when compared to that of control animals. The maximal antiepileptic effect of taurine was observed when the amino acid was administered 30-60 min previous to penicillin. It is suggested that high concentrations of taurine in the brain might be necessary to inhibit the epileptic activity.