I take Natrol brand BioBeads Acidophilus Complex every morning before breakfast. Biobeads (and others on the market) are in a shell that protects the probiotics from dissolving until they reach your intestine, where it is really needed.
I find this an important part of the whole routine of high fiber, low fat,etc.
It has been found that peole with IBS and other intestinal disorders are lacking in the natural flora that acidophilus complexes are a part of.
I am one that wants to know the causes and try to eliminate the reasons for my IBS, not just to control it and the acidophilus has been an important part of my improvement.
Everyone is different, so good luck to your search, Barb