Objective To investigate the protective effect of Modified Sini Powder（Modified powder for treating cold limbs）on hippocampus injury in chronic stressed depression rats.Methods Multi-stressors were adopted to establish the rat model of chronic stressed depression.Totally 30 male Wistar rats were randomly divided into 3 groups:the control group

model group

and Modified Sini Powder group.Hippocampal neuron apoptosis rate

content of brain-derived neurotrophic factor（BDNF）and its receptor TrkB protein

and Ca2+ concentration in neurons of each group were observed.Results Stressed rats in the model group had significantly higher hippocampal neuron apoptosis rate than those in the control group

BDNF and its receptor TrkB were decreased in expression

and Ca2+ concentration in neurons was significantly higher（P<0.05 or P<0.01）.In the Modified Sini Powder group

hippocampal neuron apoptosis rate was lowered

BDNF and TrkB protein expression increased

and Ca2+ concentration in neurons decreased

the difference was significant in comparison with those of the model group（P<0.05 or P<0.01）.Conclusion Modified Sini Powder can improve depression by up-regulating the expression of BDNF in hippocampal neurons and decreasing intracellular Ca2+ concentration.