Do probiotics work for dogs?
Updated 4 November 2026. 4 minute read.
Short answer: Probiotics help most in short, predictable situations: a change of food, kennels, or a dog with a sensitive stomach. Give them for at least five days. Loose stools lasting more than 48 hours need a vet.
When probiotics help
The good evidence is for short-term upsets: loose stools from a food change, stress or kennels. Probiotics shorten how long these last in many dogs.
For long-term tummy problems, a probiotic may help, but the cause matters more. That's a job for your vet.
What to look for on the label
In the UK, live bacteria in pet food must be an approved gut flora stabiliser. Look for the strain name and number, such as Enterococcus faecium NCIMB 10415, and the amount in CFU (colony-forming units).
A prebiotic fibre such as inulin feeds the bacteria. Pumpkin or kaolin help firm stools.
How long to give them
Give a probiotic for at least five days. For a planned food change, start a few days before and continue for a week after.
Common questions
Can I give my dog a human probiotic?
It's best not to. Human products use different strains and amounts, and some contain sweeteners like xylitol, which is poisonous to dogs.
When are loose stools an emergency?
Call your vet if there's blood, vomiting, your dog is lethargic or off food, or it lasts more than 48 hours. Puppies and old dogs need a vet sooner.
This page is general advice, not a diagnosis. If you're worried about your dog, speak to your vet.