CFU stands for colony forming unit, which describes the number of cells that can multiply and form a probiotic colony.
It is generally accepted that supplements should contain at least 1 billion CFU per strain. Supplements with this lower number can facilitate supplementation by helping to prevent excessive gas formation or bloating.
CFU counts in supplements can be as high as 50 billion CFUs. Also check the label to ensure that the CFUs are preserved and not just alive during the manufacturing process.