Each sachet of Optibac Bifido & Fibre provides 25 billion friendly bacteria + 4g of Fructooligosaccharide (fos) fibresscientifically proven to pass through stomach acidity and survive to reach the gut. Bifido & Fibre is a synbioticwhich means it combines both live cultures and Fructoologiosaccharides (fos) fibres,  FOS fibres increase your levels of natural gut bacteriain particular Bifidobacteria