Lactobacillus
Lactobacillus acidophilus – 132,000,000 CFUs per serving
According to the Mayo Clinic, "L. acidophilus is thought to benefit health, since it produces vitamin K and lactase."
And according to the University of Maryland Medical Center, "L. acidophilus breaks down food in the intestine, several substances are formed (such as lactic acid and hydrogen peroxide) that create an unfriendly environment for 'bad' bacteria."
Bifidobacterium
Bifidobacterium bifidum – 37,000,000 CFUs per serving
B. Bifidum is by far the most common probiotic bacterium in your body. The probiotic is found in the colon, the lower small intestine and in breast milk. Bifidobacterium Bifidum is often found in healthy vaginas.
B. Bifidum directly competes with Candida & yeast overgrowths in our bodies. Candida infections are commonly associated with low concentrations of B. Bifidum.
Research has shown that Bifidobacterium Bifidum produces natural antibiotic substances that kill bad bacteria. B. bifidum is also extremely susceptible to being killed by pharmaceutical antibiotics.
References
• Effect of Bifidobacterium bifidum and Lactobacillus acidophilus on gut mucosa and peripheral blood B-lymphocytes. Immunopharmacol Immunotoxicol. 1992;14(1-2):331-40.
• Effect of Lactobacillus gasseri PA 16/8, Bifidobacterium longum SP 07/3, B. bifidum MF 20/5 on common cold episodes: a double blind, randomized, controlled trial. Clin Nutr. 2005 Aug;24(4):481-91.
• Prebiotic evaluation of a novel galactooligosaccharide mixture produced by the enzymatic activity of Bifidobacterium bifidum NCIMB 41171, in healthy humans: a randomized, double-blind, crossover, placebo-controlled intervention study. Am J Clin Nutr. 2008 Mar;87(3):785-91.
• Feeding of Bifidobacterium bifidum and Streptococcus thermophilus to infants in hospital for prevention of diarrhoea and shedding of rotavirus. Lancet. 1994 Oct 15;344(8929):1046-9.