I don't know. Dogs are a different species, their bacteria-flora, are very different from our own. Probiotics made for humans are not the same bacterial probiotics made for canines or other species. I'd suggest purchasing a probiotic blend made specifically for dogs. Most high quality probiotics for pets can be purcahsed at local retailers or health food stores that have a pet section. Whole Foods is a good place for this sort of thing or shopping online. I don't trust the crap at most pet stores as far as being anything of quality.