Natural Factors Ultimate Probiotic Critical Care 55 Billion provides 9 gastric-resistant strains with a powerful concentration of 55 billion CFU of live bacteria to support a healthy digestive and immune system. Each capsule contains probiotic strains chosen for their hardiness and viability to withstand the journey through the intestines, helping to ensure maximum absorption in the small intestine (where digestion primarily takes place). Formulated to help restore a healthy balance of microflora when gastrointestinal health may be compromised, Ultimate Probiotic Critical Care also provides probiotic support to help relieve occasional bloating, irregularity and indigestion. This gentle and safe, non-GMO dietary supplement is third-party certified by ISURA, which tests for GMOs and over 600 contaminants.