The present experiment was designed to examine catecholamines, 5-hydroxytryptamine, amino acids. malondialdehyde(MDA) and free radical scavenging activity, by administering Chilbokyeum extracts of a variety of concentration to senile brain rats. The results were summarized as followings ; 1. Chilbokyeum significantly increased noradrenalin in the hippocampus and hypothalamus of the brain tissue of senile rats, ad even though Chilbokyeum increased noradrenalin also in other brain tissue, there was no significance. 2. Chilbokyeum had no effects on dopamine changes in all brain tissue of senile rats.3. Chilbokyeum significantly increased 5-hydroxy-tryptamine in cerebellum, but decreased in other brain tissue.4. Chilbokyeum increased amino in the brain tissue of senile rats. 5. Chilbokyeum significantly decreased MDA and free radical in the brain tissue of senile rats. According to the above results, Chilbokyeum is assumed to improve brain function by reaction by reacting on biochemical of the senile brain, and that Chilbokyeum can be used to treat regressive brain disease carrying symptoms of psychoactive disorders.