The Microbiome refers to the millions of bacteria within each person. Natures Aid Pro-100 Ultra is a daily supplement that provides 100 billion live organisms from 8 different strains of bacteria, including Lactobacillus Acidophilus, Lactobacillus Casei, Lactobacillus Reuteri, Lactobacillus Plantarum, Streptococcus Thermophilus, Bifidobacteria Lactis, Bifidobacteria Longum, and Bifidobacteria Bifidus. Each pack contains 30 capsules. The supplement is vegetarian and vegan, and contains no artificial colours, flavours, or sugar. The bacteria used in Pro-100 Ultra are proven to reach the gut intact and are antibiotic resistant. This formula was developed by bio-chemists and nutritionists based on scientific research to support the delicate internal ecosystem that can be affected by factors like antibiotics and illness.