In the July issue of Consumer Reports that just came out, there is a 2 page article about probiotics. Addressed are the benefits and also a ratings of some different probiotics. CR tested the actual levels of probiotics in several different brands and found some to be substantially lower than the label stated. It's an interesting article, you may want to head to your local bookstore and read it. There's also a paragraph on gastrointestinal relief which emcompassed IBS.