I respectfully disagree with the response that was given to your post. The bacteria in the gut is impacted by numerous factors over our lifetime. Anything from illness to stress to medication use can skew the number and count of bacterial organisms in the intestinal tract. That, in turn, can quickly or more slowly lead to dysfunction.
I believe probiotics can be beneficial for many things, including just general good health. If you do some reading on the subject, you'll find that the chemicals given off by the bacteria may be necessary for the health of the cells in the colon as well as mood and health of the 'mind.' Considering that fecal transplant - all those 'glorious' bacteria - is now being considered to be a possible 'cure-all' for a very horrendous condition called C. difficile infection - a situation that can lead to serious illness and even death in some cases - spending a few dollars on supplementing your pre-existing flora seems rather easy and inexpensive.
Some bacterial products have also been shown in clinical trial to be able to assist some persons with ulcerative colitis/pouchitis into remission.
The only caveat to taking probiotics might be if someone is suffering from pancreatitis or an 'incompetent' sphincter of Oddi, which might allow/result of reflux of the bacteria into the bilitary system. If either of those conditions exist, a doctor's opinion should be sought out.
If you arent having any digestive problems, I wouldn't even bother. They are't vitamins. They are more for ppl who's gut flora isn't balanced. Sounds like your flora is fine.
If you want to take them, I don't see them creating a problem. But if you notice more of a loose stool, I'd stop.