Objective To study the optimal concentration of Ciwujia Injection for rat bone marrow stromal cells differentiating into neuron-like cells in vitro.Methods The density-gradient technique was used to separate and culture the bone marrow stromal cells and the different concentration of Ciwujia Injection was applied for inducement in vitro.The growing of cells of all groups was determined with MTT and the neuron-like cells of each group were calculated by immunocytochemistry examination for comparison.Results With inducement of Ciwujia Injection in different concentrations

the cells of all groups were typically shaped like neurons.Of them

the growing of cells in 0.3mgml and 0.4mgml groups and their immunocytochemistry results were both showing differences from other groups in statistics（P<0.05 or P<0.01）.Conclusion The concentration of 0.3～0.4mgml was optimal for inducement of bone marrow stromal cells differentiating into neuron-like cells in vitro in adult rats.