Kainic acid can simulate excitatory amino acids in vitro. Neural stem cells, isolated from newborn Wistar rats, were cultured in vitro and exposed to 100-4 000 μM kainic acid for 7 days to induce neuronal cell differentiation, causing the number of astrocytes to be significantly increased. Treat-ment with a combination of 0.5 mg/L gastrodin and kainic acid also caused the number of differen-tiated neurons to be significantly increased compared with treatment with kainic acid alone. Ex-perimental findings suggest that gastrodin reduces the excitability of kainic acid and induces neural stem cell differentiation into neurons.