In the United States, recent trends have demonstrated that probiotics are increasingly added to products geared toward consumer health and wellness (Oster 2017). The recent growth has resulted in consumer education, industry expansion, and increased regulatory scrutiny. This chapter is intended to provide an overview of how probiotics are controlled within the U.S. regulatory landscape. Because probiotics do not neatly fit within a single regulatory category, it is essential to provide a review of the range of possible categories where probiotics are currently included as ingredients today, the breadth of regulatory responsibility of the U.S. Food and Drug Administration (FDA), and how probiotics fit within.