To investigate the effects of paeoniflorin on monoamine neurotransmitters in the brain tissue of chronic unpredictable stress depression rats.The 48 SD male rats were randomly divided into blank control group,depression model group,fluoxetine 10 mg/kg,paeoniflorin group (40,20 and 10 mg/kg).The rats model of chronic stress depression was established by solitary and chronic mild unpredictable stress.All groups of animals were administered for 10 min before stress for 28 days,once a day.After the administration,the hippocampus,cortex,and hypothalamus tissue of rats was taken out.The monoamine neurotransmitters ［norepinephrine(NE),dopamine(DA),5-hydroxytryptamine(5-HT),And 5-hydroxyindoleacetic acid (5-HIAA)］ content changes of material could be detected by high performance liquid chromatography (HPLC).Compared with the model group,after the administration of paeoniflorin 40 and 20 mg/kg,the contents of NE,DA,and 5-HT increased obviously,while the content of 5-HIAA decreased obviously in the hippocampus,cortex,and hypothalamus.Paeoniflorin 10 mg/kg could increase NE levels in cortical tissue,NE and 5-HT levels in hypothalamic tissue,and also reduce 5-HIAA levels in cortex and hypothalamic tissue.Paeoniflorin can significantly play the role of anti-depression by regulation the level of monoamine neurotransmitters in the hippocampus,cortex,and hypothalamus tissue of rats,which may be related to the pharmacological mechanism of anti-depression action.