Probiotics for Dogs: Do They Work and Which to Choose

By Tailwisp Editorial TeamUpdated October 17, 20263 min read

The gut contains trillions of microorganisms that help digest food, train the immune system and keep harmful bacteria in check. Probiotics aim to support that community. They are popular for dogs, but how well do they work?

What probiotics are

Probiotics are live microorganisms, such as certain strains of Enterococcus faecium, Lactobacillus and Bifidobacterium, or the yeast Saccharomyces boulardii, that may provide health benefits when given in adequate amounts. They are different from prebiotics, which are fibres that feed beneficial gut bacteria, and from synbiotics, which combine both.

What does the evidence show?

Research in dogs is growing but still limited, and results depend on the strain.

• Acute diarrhea. Some studies show certain strains can shorten the duration of mild diarrhea.
• Antibiotic-associated diarrhea. Probiotics may reduce gut upset during antibiotic treatment.
• Stress colitis. For dogs that get loose stools when boarded or travelling, probiotics may help.
• Chronic enteropathies. Evidence is mixed, and treatment must be guided by a vet.
• Allergies and other conditions. Evidence is weak.

Probiotics are not a cure for serious disease. See our guide to diarrhea in dogs.

Choosing a product

Quality varies widely. Studies have found that many products do not contain the strains or numbers on the label.

• Choose veterinary-recommended brands with published evidence.
• Look for specific strains, not just species names, and guaranteed colony forming units through the end of shelf life.
• Check storage requirements, since some need refrigeration.
• Avoid products with xylitol or other harmful ingredients. See xylitol.
• Ask your vet.

Forms

Probiotics come as powders, chews, capsules and pastes. Powders can be mixed into food. Some foods include probiotics, but the live counts may not survive processing and storage.

Are yogurt and fermented foods enough?

Yogurt contains live cultures, but the strains are not always the ones that help dogs, and counts are variable. See yogurt for dogs. Kefir and fermented vegetables are also unreliable and may not suit sensitive dogs.

Dosage

Follow the product label and your vet's advice. Dosing depends on the strain and weight. Start gradually, and use for the recommended time.

Safety

Probiotics are generally safe, with mild gas or bloating as the most common side effect. Dogs with severely weakened immune systems, central lines or serious illness should only use them under veterinary supervision, because live organisms can occasionally cause infection.

When to call the vet

Do not rely on probiotics if your dog has bloody diarrhea, vomiting, fever, lethargy or diarrhea lasting more than a day or two. Puppies and seniors can dehydrate quickly. See sensitive stomach diets for dietary support.

Prebiotics and fibre

Fibres such as beet pulp and psyllium feed gut bacteria. See fibre for dogs.

Using probiotics around stressful events

Many owners find probiotics most useful around predictable stress, such as boarding, travel, vet visits or a change of diet. Starting a product a few days beforehand and continuing for a short period afterward is a common approach, though you should check the plan with your vet. Keep routines calm, and avoid changing too many things at once, since gut upset often comes from several small stressors combined.

Signs a probiotic is not the answer

If your dog loses weight, has recurring diarrhea, bloody stools, vomiting or a swollen belly, the problem needs investigation. A probiotic may mask signs for a while, but the underlying cause, such as parasites, food intolerance or chronic disease, will remain. Bring stool samples to your vet, and keep a log of what your dog eats and how stools look.

The takeaway

Probiotics may help with short-term digestive upset. Choose a quality product, give it a fair trial and see your vet if problems persist.

This article is general educational information, not veterinary advice. Every dog is different. If your dog is unwell, or you are unsure about a symptom, diet change or medication, contact your veterinarian.