The link below is interesting. http://www.mercola.com/2001/jul/11/probiotics.htm I think that probiotics definitely helped me when i had very bad diarrhea. Homemade yogurt was an even bigger help until I became intolerant of it.However, I am not experiencing a miracle cure and I have been taking primal defense (now--VSL#3) for about 4 months straight. Prior to that i took several different brands PB8, kyodophilus, natures way.The probiotics are supposed to help reduce immune reactions in the gut. This may be happening but i am not noticing it. However, the Ibsacol is definitely doing that --it may give out but right now and in the past it has worked.I am going to continue to take probiotics because they may be helping with other things.besides i think that if i take the VSL#3 for at least a year then there should definitely be a change in my colonic bacteria makeup.I know I am a carrier of the sulfur producing bacteria because i had the smell most of my life.now when i pass gas the odor is either non-detectable or very low.However, when i went off my no sugar/no fruit diet the odor came back after about 5 days and the gas volume tripled but it was still within reason.