The anticonvulsant effects of Shitei- To and its components on maximal electroshock seizures and chemical convulsions were examined. Shitei-To significantly prolonged the latency to bicuculline (2.0 mg/kg, s.c.)-induced clonic convulsions. Repeated treatment with Shitei-To also significantly prolonged the latency to strychnine (1.5 mg/kg, i.p.)- and pentylenetetrazol (90 mg/kg, i.p.)-induced clonic convulsions. On the other hand, Shitei-To had no effect on maximal electroshock seizures. Of the components of Shitei-To, Shitei had almost the same effect as Shitei-To against the clonic convulsions induced by the three chemical agents tested. These findings suggest that Shitei-To has anticonvulsant effects.