中文摘要：

考察人体口腔异味现象，利用恒化器建模方法，改进了人体口腔系统中微生物种群关系的模型，利用Lyapunov稳定性理论分析了系统的平衡点及其稳定性．进而得到结论，口腔异味作为疾病，需要专业医治才能治愈．数值模拟结果证实了理论分析的正确性．

英文摘要：

In this paper, we consider phenomenon of oral oder. Firstly, after the assumption of ration-dependent increasing rate function, we set up the ordinary differential equations models for the relations between human oral microorganism populations. They are chemostat models that have been widely applied in both mathematical and biological fields. Secondly, using the Lyapunov stability theory, we analyze asymptotic behavior for solutions of differential equations＇ models and get the stability results for the balance nodes. Then we have the main result.- bad breath, as a disease, should be cured by professional methods. Simulation results prove our results.