Human gut microbiota consists of various microorganisms whose numbers are similar to those of human cells. Human gut microbes and the brain form bidirectional communications through the brain-gut-axis, and play a central role in normal physiological processes and in pathogenesis of many human diseases. Accumulating evidence has demonstrated the crucial effect of gut microbes in proper brain functions and under disease conditions. Here we first focus on revealing current knowledge of the role of gut microbes in neural development and functions. We then summarize mutual relationships between gut microbes and human diseases, in particular neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease and Multiple sclerosis. Finally, we highlight ongoing studies in exploring gut microbes in treatments of human diseases. Applying gut microbes as a means in treatment of human diseases is becoming a promising research direction, and has a great potential in clinical practice.

人肠道菌群由数量与人细胞数量相似的各种微生物组成。人类肠道微生物和大脑通过脑肠轴形成双向通讯，并在正常生理过程和许多人类疾病的发病机理中发挥重要作用。越来越多的证据表明，肠道微生物在适当的脑功能和疾病条件下具有至关重要的作用。在这里，我们首先专注于揭示肠道微生物在神经发育和功能中的作用的当前知识。然后，我们总结了肠道微生物与人类疾病之间的相互关系，特别是神经退行性疾病，例如阿尔茨海默氏病，帕金森氏病和多发性硬化症。最后，我们重点介绍了在探索肠道微生物治疗人类疾病方面正在进行的研究。