The CFU Myth
CFU (Colony Forming Units) is a measure of live microbes. Marketing departments have engaged in an arms race, pushing 50B, 100B, and 200B CFU products.
The Science
Clinical efficacy plateaus. If a strain is proven to bind to the intestinal wall at 5 Billion CFU, taking 50 Billion does not yield 10x the binding. Often, these mega-dose products use cheap, unresearched strains to pad the numbers.