Despite the hyperbole often linked with a popular research field, the scientific rationale for probiotics is sound. The probiotic concept is not new but is undergoing transition as knowledge of the gut microbiota in health and disease becomes translated to the clinic. Operationally, a probiotic represents a mimic of and/or supplement to the normal gut microbiota. Much confusion has arisen among consumers because of media misportrayals of probiotics as all being the same. Science is catching up to change the common misconceptions.