We use Theralac. Place ".com" after the name and you can read about
it. I order it from the company. It is somewhat pricey. More than some, less than others. I think there are several good ones out there. I've always been told that those which require refrigeration are better. Who knows.
VSL#3 is often discussed here and has been used to treat Crohn's patients. You might look into it. It is very pricey, though, but some docs will prescribe it, so you might get insurance to offset cost.
In any case, I believe most here would agree that probiotics are very beneficial. I take them just for good measure--I don't have GI issues.
Good luck to you!