We're learning more about keeping bowels cleansed and healthy, too. I'm totally new to all this, but dh has used some bowel cleansing products made by herbalist Dr. Richard Schultz. I won't provide a link b/c he does sell products and his site and published materials are peppered with "colorful" language here and there. But he seems very knowlegeable and gung ho about healthy bowels. It's interesting stuff. You can just google his name and you'll find his website.
I have never used probiotics.. still assimlilating all these different "natual living" ideas.