I have dealt with a dog that had IBD for years, (now deceased) and don't waste your money on most of those probiotics. Use a natural yogurt, with Live Active Cultures, should say so on the label, and feed that. Dannon also makes a probiotic drink, can't remember the name right now, that is high in active cultures. Some grocery stores carry it.
If you do want to go with a supplement, buy one from the health food store, the ones that will actually work are kept refridgerated, just open a capsule and sprinkle on food.
I don't know if this will help, but Solid Gold came out with a canned tripe, called Green Cow, that is supposed to be very high in natural enzymes, and good for digestion. I started feeding it to my dogs and they love it. Don't know if it will help with your current problem, but after your pups tummy settles down, it may be worth a try for maintenance.
http://www.solidgoldhealth.com/produ...id=60&code=260