Abstract

There is a general scientific consensus that the microbiota plays an important role in maintaining human health.This is most emphasised for the intestinal microbiota, but is likely equally true for the microbiota in/on other sites of the body.International research programmes aim at identifying the composition of the human microbiota. The challenge, however, isto determine what actually is/are the health promoting component(s) of the microbiota. Absence of (potential) pathogenic microbes is one possibility. Instead of thinking in terms of “good” and “bad”; it might be worthwhile to considerthe microbiota as a whole and strive to maintain or restore its composition during or after challenges.