Objective:To study the sedative and hypnotic effect and mechanism of Cordyceps militaris polysaccharide（CMP）and Cordyceps militaris flavonoids（CMF）on the base of the automatic activity of mice and contents of acetylcholine（Ach）

glutamate（Glu）

5-hydroxytryptamine（5-HT）and gamma amino butyric acid（GABA）in mice’s brain. Methods:Totally 84 ICR mice were randomly divided into 7 groups and orally administrated with water

CMP 50 mg/kg

100 mg/kg

200 mg/kg and CMF 50 mg/kg

100mg/kg

200 mg/kg respectively. Fourteen days later

the automatic activities of ICR mice were observed and recorded. Thirty days later

contents of 5-HT

Ach

Glu and GABA in mice’s brain were determined by ELASA method. The effect of CMP and CMF on the proliferation of PC12 cells was detected by MTT assay. Results:Automatic activity analysis showed that the independent activity frequency was significantly lower in CMP（100 mg/kg and 200 mg/kg）and CMF（100 mg/kg and 200 mg/kg）groups than in control group（P=0.000）. Results of neurotransmitter levels showed that Glu levels were significantly lower in CMP（100 mg/kg and 200 mg/kg）and CMF（50 mg/kg）groups（P=0.000）than in control group;the Ach levels were significantly lower in CMP（200 mg/kg）and CMF（200mg/kg）groups than in control group（P values were 0.003 and 0.000 respectively）

while 5-HT levels were completely opposite to the Ach levels in these two groups（P=0.000）. No change was found according to the GABA level in mice’s brain. MTT assay results showed that no toxicity has been noticed and CMP with 1 μg and 0.1 μg groups could also promote the cell proliferation of PC12.Conclusion:The results showed that polysaccharide and flavonoids of Cordyceps militaris had significant sedative-hypnotic effect. The mechanism may be related to increase 5-HT level and decreased Ach and Glu levels in brain.