My puppy was dealing with bacterial issues when he was younger, and was having difficulty eating food without having an episode of diarrhea. After consulting with my veterinarian, she set me on the path to Fortiflora. We put him on a packet a day, and we started to see some improvement within a month. After continuing the use of the product, we saw significant improvement. He is now over a year old and only has the occasional episode of diarrhea, and this is usually only when he gets into something that he should not. I would say that the Fortiflora worked for our dog, but you should always consult with your veterinarian before you try anything new with a new puppy.