消化道上下两端向外开放、内部与各个器官相通。因此肠道内容物与外界及其他器官经常进行物质、能量或信息交流。大肠中共生的种类繁杂、数量巨大的细菌 ,犹如千军万马 ,菌群激荡。在正常情况下对宿主健康有益 ,一旦粘膜出现纰漏、腔菌群侵入 ,或其毒性代谢产物被粘膜吸收 ,则? Upper and lower ends of the digestive tract open to the outside, the internal organs communicate with each other. Therefore, intestinal contents and the outside world and other organs often exchange material, energy or information. Colony of the complex species, a huge number of bacteria, like a mighty force, flora agitation. Under normal circumstances, beneficial to the health of the host, once the mucosa flaws, flora invade, or its toxic metabolites absorbed by the mucosa, then?