Could probiotics be the answer to boosting your immune system? 80% of your immune system is found in your gut, so of course gut function is of vital importance. When you want to boost your immune system start by repairing your digestive system function and health. One of the most fundamental aspects of your digestive function is your healthy gut microflora, which is good bacteria. These bacteria colonise your gut and help with absorption of nutrients and protection from other pathogens. The best way to maintain this gut bacteria is with the use of probiotics, not only will they help with gut function but also with immune system function.