Abstract:Conditioned pathogen was a basic concept widely used in domestic medical microbiology textbook. However, there were obvious defects both in the establishment and application of this concept. And which might make students misunderstand and be ambiguous when learn some essential fundermental cocepts, such as symbiotic microbial community in the human body and conditioned pathogen. So here we offer some initial ideas for discussion, and hope a more faultless and suitable formulation could be made by learning from each other.