It's good to be cautious when starting something new, but in this case you'll be good to go. Like Canyonbabe said, Digestive Advantage is simply a brand name for a particular blend of probiotics (many of which can be found in regular ol' yogurt); many people on this forum use this brand as well as other brands of probiotic blends. You might want to start off taking less than the recommended dose at first; some people experience an increase in gas in the first couple of days. It's kind of like if you start taking a fiber supplement all of a sudden, you might notice increased gas - but it will go away on its own in no time.
Good luck - probiotics have helped many people combat their symptoms of IBS (constipation and diarrhea alike) and hopefully it will work for you.