All it should do is restore balance to your flora. If severely out of balance, you should see signs both detox type annoying like rashes and positive type of feeling better/digesting better.
IT's certainly not meant to be taken forever. Once you are clean and eating good veggies, your microbial colonies should be self-managing. All you should need from then on is the occasional boost, and that can be a very minor boost of yoghurt or kefir.
While I recommend mega-doses during candida, that is only for getting a "head start" on healing and balancing. If you fail to do all the other things like extensive colon cleansing (which means a need for repopluating too) it won't matter how much you take. It is by no means a cure-all.