OBJECTIVE:To observe the effect of tribulus terrestris saponins(TTS) on behavior and neuroendocrine of chronic mild stress(CMS) depression rats.METHODS:ThirtymaleSprague-Dawleyratswererandomly allocated to six groups:vehicle group,CMS group,CMS + fluoxetine group and CMS + TTS of low-dosage(0.375g/kg),medium-dosage(0.75g/kg) and high-dosage(2.25 g/kg) groups.All rats except the vehicle group singly housed and exposed an unpredicted sequence of mild stressors.The behavior of rats was detected by open-field test(OFT) and sucrose preference test(SPT).The concentration of corticotropin-releasing factor(CRF) and adrenocorticotropic hormone(ACTH) in serum of the rats were detected by radioimmunoassay.The concentration of cortisol(CORT) in serum was detected by enzyme immunoassay.RESULTS:CMS procedure not only significantly decreased the scores of crossing,rears and grooming in OFT and the sucrose preference in SPT(all P< 0.01),but also markedly increased serum CRH and CORT levels(both P<0.05,P< 0.01).CONCLUSION:CMS can affect rat behavior and neuroendocrine and cause depression.TTS has the antagonism on CMS and produce antidepressive effects.