Background: Vagus nerve stimulation (VNS) is a neurophysiological therapy (NPT) of refractory epilepsy, which can control the seizure by stimulating the vagus nerve stem in cervical part. Objective: To study the effect of intermittent left-side VNS on seizure of epileptic animals, and provide theoretic basis for the interaction of somatic information and that of internal organs. Design: Observation st udy. Setting: Department of Neurobiology, Capita l University of Medical Science. Matreials: The experiment was performed in the Laboratory of E lectrophysiology in Department of Neurobiology, Capital University of Medical Science from March 2000 to September 2002. Thirty-four healthy adult SD rats and 8 rabbits, weighting (220-250) g and (2.2-2.5) kg respectively were selected. Methods: 1 Ten rats were intramuscularly in jected with (156 000-160 000) U of penicillin (PCN). VNS effects on epileptiform activities of rats were studied by observing the changes in electrocorticogram (ECoG) and behavior of rats before and after VNS. 2 (0.24-0.48) mg of PCN was injected into the hippocampus of another 8 rabbits to induce epilepsy, and VNS effects on ECoG of epileptic rats were observed. 3 Seizures of 16 rats were induced by Kainic acid, and changes in discharge activity of hippocampal neuron, ECoG and behavior of epileptic rats were observed after VNS. 4 Seizures of 8 rabbits were induced by cortical injection of strychnine with microinjector, and VNS effects on ECoG of rabbits with epilepsy induced by acute cortical injury were observed. Main outcome m easures: 1 VNS effects on seizure of rats with epilepsy induced by PCN. 2 VNS effects on seizure of rats with epilepsy induced by Kainic acid. 3 VNS effects on epileptiform ECoG of rabbits with epilepsy induced by strychnine. Results: A total of 34 rats and 8 rabbi ts were involved in the analysis of results. VNS could remarkably suppress the seizure of epileptic animals, and epileptiform ECoG, epileptiform discharges of hippocampal neuron and behavior significantly changed with the total effective rate greater than 50%. The total effective rate of VNS before seizure was greater than 80%. In epilepsy group induced by intramuscular injection of PCN, ECoG and behavior were markedly ameliorated respectively for 40% and 50% of rats. In epilepsy group induced by injection of PCN in hippocampus, the ECoG was significantly ameliorated in 50% rats. In epileptic rabbit group induced by partial injection of strychnine via cerebral cortex, the epileptiform wave in ECoG was controlled by VNS in 50 % of animals. Conclusion: VNS can effectively suppress seizure of ep ileptic animals. The antiepileptic effect of VNS is associated with cerebral cortical and hippcampal neurons. Somatic epileptiform activity could be effectively inhibited by the integration of visceral afferent information in cortical and hippocampal parts.