Our Probiotic Extra Strength combines five strains (Lactobacillus acidophilus, Lactobacillus casei rhamnosus, Lactobacillus bulgaricus, Bifidobacterium longum, Bifobacterium bifidum) of active probiotic cultures fortified with fructooligosacchiares designed to further enhance probiotics' beneficial effects in the lower bowel. This superior formula provides 10 billion live units per capsule, designed for more advanced probitic requriements. Finally, a guaranteed active probiotic, constantly refrigerated from the moment it is processed until it arrives in your office in a cold pack. Shipped cold packed.