VSL#3® works by colonizing the GI tract with optimal quantities and types of probiotic bacteria. These bacteria adhere to the walls of the GI tract and form a barrier which protects the inner layer of the gut from bad bacteria and other toxic substances that can cause inflammation. Using a high concentration of eight different strains of specially selected beneficial bacteria, VSL#3® produces an optimal composition of good bacteria, delivering relief from symptoms and enhancing the health of the GI tract.