Here's a link regarding research on VSL, just scroll to the top of the page when it loads in, to read the article from the beginning.
I've been taking VSL#3 capsules for almost a month, and it's had a wonderful effect. Generally, I don't have strong symptoms, but I was starting to have gas and not so great BMs. After the first couple of days I noticed a change, and since then it's been "just logs". If you can afford it, it's definitely worth a try.