PRESENTATIONProbiotics and Evidence-based Medicine To All Involved: We Have a ProblemKoch, Maurizio MDAuthor Information GI and Liver Unit, General Hospital S.Filippo Neri, Rome, Italy The author declares that there is nothing to disclose. Address correspondence to: Maurizio Koch, MD, GI and Liver Unit, General Hospital S.Filippo Neri, Rome 00165, Italy (e-mail: [email protected]). Journal of Clinical Gastroenterology: November/December 2018 - Volume 52 - Issue - p S4-S6 doi: 10.1097/MCG.0000000000001106 Buy Metrics Abstract The methods used to discern the structure (anatomy) and function (physiology) of the indigenous microbiota can be divided according to which aspect of the microbiota they can interrogate and are positioned accordingly. At the most basic level, methods can simply describe the community structure of the microbiota, that is, which taxa are present and in what relative amounts. Methods that investigate functional potential generally catalog the coding potential of individual members of the microbiota or the entire community (the metagenome). To measure function directly a catalog of the expressed microbial genes (the metatranscriptome) or the proteins or metabolites present in the microbiome environment must be generated. So, complexity in understanding the role of microbiota is quite rejecting the interested clinician. Evidence-based medicine can offer an answer suggesting strict definition of populations, measurement techniques, and external validity. Copyright © 2018 Wolters Kluwer Health, Inc. All rights reserved.