I took it for about 4 months and it was hard to tell if it helped. I switched to VSL#3 because it has 450 billion bacteria per small packet. It is $3.00 per packet but dollar for dollar it beats all the rest. however, i am half tempted to switch back to the primal defense. I won't be saving any money because i had to take between 7 and 10 pills a day. At least i think I had to take that many.Here is the most important news. Ibsacol has ---without question-- done the most for me. I know this for a fact. It may not keep on working but so far i have gained the most relief from this product.Even though i have not experienced any real noticeable effects from ANY probiotic I will continue to take them because i think that over the long haul (1 to 2 years) they will make a difference.The one exception was when i had bad diarhhea 2 years ago and was as sick as can be (i thought i was going to die) that is when probiotics helped me get better. But it was actually homemade goat milk yogurt that helped much more. ---until i became intolerant of goat milk.