Abstract： Objective To observe the effect of chaihushugantang on the expression of c-fos in the hippocampus and frontal lobe cortex of pentylenetetrazole (PTZ)-induced epileptic rats. Methods Forty-eight PTZ-induced epileptic rats were randomly divided into 6 groups: epileptic model group,Valproate treatment group, Dingxianwan treatment group, and lower-dose, medium-dose and high-dose chaihushugantang treatment groups (n=8). Normal control group was also employed (n=8). The epileptic rats in the normal control group and epileptic model group were fed normally. Rats of the treatment groups were performed intragastric administration of medicines (Valproate, Dingxianwan and chaihushugantang) for 5 weeks in succession respectively. The expression of c-fos in the hippocampus and frontal lobe cortex of all the rats was observed. Results The expression of c-fos in the hippocampus and frontal lobe cortex of rats in the epileptic model group was significantly increased, while the c-fos expression in the hippocampus and the frontal lobe cortex of rats in the medium-dose and high-dose chaihushugantang treatment groups and Valproate treatment group and Dingxianwan treatment group was significantly decreased as compared with that in epileptic model group (P<0.05). But the c-fos expression in the hippocampus and the frontal lobe cortex of rats in the low-dose chaihushugantang treatment group showed no obvious decrease. Conclusion Chaihushugantang has good antiepileptic effect, might through affecting the c-fos expression in the epileptic rats. The antiepileptic mechanism of chaihushugantang can be related to saikosaponins and other antiepileptic constituents in it.