Objective To explore the potential mechanism of Zuogui Wan（左归丸） and Yougui Wan（右归丸） in improving sleep imbalance. Methods Twenty-five Sprague Dawley（SD） rats were randomized into the normal control group

the insomnia model group

the sleepiness model group

the Zuogui Wan group and the Yougui Wan group

with 5 rats in each group. Rats in the insomnia model group and the Zuogui Wan group were made insomnia models by type 1 A 5-hydroxytryptamine（5-HT1 A） receptor blocker WAY 100635 microinjection into dorsal raphe nucleus. Rats in the sleepiness model group and the Yougui Wan group were made sleepiness models by 5-HT1 A receptor agonist 8-OH-DPAT microinjection. The normal control group was given equivalent normal saline microinjection into dorsal raphe nucleus

for 3 days. Two hours after the last injection

rats in the Zuogui Wan group was given Zuogui Wan solution 17. 5 g/（kg · d） by gavage. The Yougui Wan group was given Yougui Wan solution 18. 5 g/（kg·d） by gavage. Rats in the other 3 groups were given 10 ml/（kg·d） distilled water by gavage

once every day

for 7 days. The levels of monoamine neurotransmitter dopamine（DA）

dihydroxyphenylacetic acid（DOPAC）

5-hydroxytryptamine（5-HT） and 5-hydroxyindoleacetic acid（5-HIAA） in rats’ plasma in each group were determined by high performance liquid spectrum method; 5-HIAA/5-HT was calculated. Results Compared with the normal control group

the levels of plasma DA

DOPAC and 5-HIAA as well as 5-HIAA/5-HT in the insomnia model group increased（P < 0. 01）; while those in the sleepiness model group decreased（P < 0. 05 or P < 0. 01）. Compared with the insomnia model group

the levels of DA

DOPAC and 5-HIAA as well as 5-HIAA/5-HT in the Zuogui Wan group decreased（P < 0. 05 or P < 0. 01）. Compared with the sleepiness model group

the levels of DA

DOPAC and5-HIAA as well as 5-HIAA/5-HT in the Yougui Wan group increased（P < 0. 01）. The difference of 5-HT level in rats’ plasma in each group was not significant（P > 0. 05）. Conclusion Zuogui Wan might reduce the excitatory neurotransmitters in insomnia rats

while Yougui Wan might increase the excitatory neurotransmitters in sleepiness rats. Both might improve sleep imbalance by balancing neurotransmitters.