The ONLY probiotic made just for dogs: many probiotic product sold for dogs are human probiotics with a new label for dogs. The native flora for a dog is different than humans and PRO6 contains the 6 strains of bacteria native to the canine digestive tract. 2 BILLION CFU's - any product offering less will not be effective for your dog. NO ADDITIVES - many other products add other ingredients or compounds that are not necessary for a probiotic. PRO6 contains only what your dog needs. CHEWABLE - no cheese, peanut butter, or pill pockets are necessary. A small naturally flavored chewable tablet will be easy for your dog to enjoy like a treat. GUARANTEED - HardyPet offers a 30 day guarantee that your dog will have a healthier digestive tract or your money back.