Costco sells several probiotic supplements that contain various live bacteria strains. These probiotics are intended to support digestive and immune health by repopulating beneficial gut bacteria. The document describes eight probiotic products sold at Costco, including iFlora with 16 strains and 32 billion cells, chewable probiotics with 5 billion cells of three strains, and Friendly Force with 150 billion cells of six strains. It also mentions Culturelle and Kyo-Dophilus probiotics and their intended benefits. The author's favorite probiotic, Probacto, is noted but not currently sold at Costco.