Make sure that the form of probiotic (capsules, powders, chews, and dietary sources) you are opting for is suitable for your dog to consume.)
Look for probiotic strains that have been proven to be beneficial for dogs, such as Lactobacillus acidophilus or Bifidobacterium animalis.
Also check the CFU (colony forming unit) count because a higher CFU suggests that the probiotic is potent.
Last but not the least, consider buying probiotics supplements for dogs from a reputable brand, preferably one that has been recommended by your veterinarian.