Nelumbo nucifera(NN) is a oriental medicinal herb which has been used traditionally for the treatment of antidiarrhea, sedative action and various brain diseases including convulsion and epilepsy. In order to examine the mechanism of anticonvulsive effect, we treated the methanol extract of NN(100, 200 mg/kg, P.0) to the sleeping time and pentylenetetrazole(PTZ)-induced convulsive mice. The methanol extract of NN prolonged sleep time by pentobarbital. Methanol extracts of NN were not effected the concentration of GABA and GABA-T activity in the brain of PTZ-induced mice. Methanol extracts of NN significantly inhibited the convulsion state as well as the level of lipid peroxidation in the brain. The butanol and dichloromethane fraction of methanol extracts among the others effectively inhibited in vitro lipid peroxidation dose dependently($5.0{ imes}10^{-6}sim2.0{ imes}10^{-5};g/ml$). These results suggest that the anticonvulsive effect of NN is possibly due to the antioxidative effects of the free radical formation at brain for the PTZ-induced convulsion if it were by due to generating system.