Our doctor recently advised us to take Acidophylis. This is good bacteria in a capsule that isn't broken down by the upper gut but stays in tact until it reaches the lower part where its really needed. It seems that trials are going on at the moment in hospitals where patients are being given acidophylis or placebos following major surgery. The numbers of patients on the acidophylis not contracting infections following the surgery is very encouraging. Make sure you buy from a good health store and get the one with at least 2 billion active bacteria (beware there are cheaper low content versions out there). You may only need a one month course to have your gut in good condition. Hope this helps