Probiotics are only one part of a whole body approach system. Like some of the previous posters mentioned, you have to treat your body like an organic plant. As above, so below.
Think about how much dank you would grow if you fed your plant only macerated cheeseburgers and coca cola. The body needs a certain pH to function and the proper amount of nutrients and sugars to fuel it. That probiotic on the first page looks good to me. Broad range probiotics (human mycorrhizae and thrichoderma) break down the food we eat in combination with the Fulvic and Humic Acid (Same effect in humans as plants) chelates it so we can absorb them better. Pure water is necessary as like said the chlorine and chloramines will diminish the flora units. A blood change of just 1.0 pH in either direction could kill off significant aerobic microorganisms. In this regard, it is important to continually supply your body with more organisms by continually taking the supplements. There is no doubt that 90% of environmental intakes destroy these microorganisms so for best effect you will need to shell out some dough... That's the NON gimmick side.
You have to have exercise and proper eating habits and ways to positively deal with stress and anxiety or no amount of gut flora will make your digestive system better, miraculous or otherwise.
After all, you are what you eat. "Let food be thy medicine and medicine food." ~Hippocrates