Probioticfrom firmRevivecontains 5 scientifically based and tested probiotic strains. This blend of tested strains was chosen because of the strains' ability to enter the gastrointestinal tract and colonize, unlike many other probiotics on the market today. Probiotics, which can be cultured once they reach their destination, help balance the ratio of good and bad bacteria in the gut. As the ratio becomes more balanced, gastrointestinal health improves.