Best probiotic for dogs
For most dogs, Purina FortiFlora: one packet a day for any size dog, $1.03 a day. It prints its exact strain (SF68), carries the NASC seal, and a 2011 lab test found 2.6 times the bacteria on its label, one of 2 of 25 products to pass every check.1 For the lowest cost, Horbäach River & Rula ProBi-Pet Digestive Aid Chewable Tablets (Horbaach), dogs and cats gives 500 million CFU a day for $0.08 for a 50 lb dog.
Best for most dogs
Purina FortiFlora Probiotic Powder
100 million CFU a day (1 packet)exact strain (SF68)$1.03 a day for a 50 lb dog2
Best value
Horbäach River & Rula ProBi-Pet Digestive Aid Chewable Tablets (Horbaach), dogs and cats
500 million CFU a day (2 tablets)species named$0.08 a day for a 50 lb dog3
Best value with the NASC seal
Pet Naturals Daily Probiotic Soft Chews
240 million CFU a day (2 chews)species named$0.23 a day for a 50 lb dog4
We pick by what the label names (strain or species), the NASC seal, and cost a day for a 50 lb dog. Prices on Amazon, October 28, 2026.5, 6
Dog probiotics at a glance
The 35 probiotics we compared, for a 50 lb dog
On the label, look for a strain code like SF68, the CFU count (live bacteria), and the NASC seal. From each brand's label panel and Amazon listing.
What our picks cost by dog size
FortiFlora is one packet a day for every dog, so it costs the same for a chihuahua and a mastiff. The others scale with weight. Horbäach gives 1 scoop per 50 lb.
Cost a day at the label dose for that weight, with the CFU it gives.
| Product | 10 lb | 25 lb | 50 lb | 75 lb | 100 lb |
|---|---|---|---|---|---|
| Purina FortiFlora Probiotic Powder | $1.03 a day 100 million CFU | $1.03 a day 100 million CFU | $1.03 a day 100 million CFU | $1.03 a day 100 million CFU | $1.03 a day 100 million CFU |
| Horbäach River & Rula ProBi-Pet Digestive Aid Chewable Tablets (Horbaach), dogs and cats | $0.04 a day 250 million CFU | $0.08 a day 500 million CFU | $0.08 a day 500 million CFU | $0.17 a day 1 billion CFU | $0.17 a day 1 billion CFU |
| Pet Naturals Daily Probiotic Soft Chews | $0.11 a day 120 million CFU | $0.11 a day 120 million CFU | $0.23 a day 240 million CFU | $0.34 a day 360 million CFU | $0.45 a day 480 million CFU |
The 35 dog probiotics we compared
Cheapest a day first, for a 50 lb dog at the label's own dose. Only products sold by Amazon.com or the brand.
Exact strain = the label prints a strain code. Species named = it lists the bacteria, like L. acidophilus, but no strain code. Not named = the label names no bacteria. CFU a day = the label's dose for a 50 lb dog times the CFU in each serving. Cost a day = that many servings at the Amazon price read October 28, 2026.
| Product | Strains on the label | CFU a day, 50 lb | NASC seal | Cost a day |
|---|---|---|---|---|
| Horbäach River & Rula ProBi-Pet Digestive Aid Chewable Tablets (Horbaach), dogs and cats | Species named | 500 million CFU (2 tablets) | No | $0.08 a day |
| Nusentia Probiotic Miracle Powder | Species named | 1 billion CFU (1 scoop) | No | $0.11 a day |
| SnazFirst Probiotic Chews (Chicken) | Species named | 4.8 billion CFU (4 chews) | No | $0.19 a day |
| Pet Naturals Daily Probiotic Soft Chews | Species named | 240 million CFU (2 chews) | Yes | $0.23 a day |
| WEALLIN Probiotic Chews (Chicken) | Species named | 3 billion CFU (3 chews) | No | $0.27 a day |
| TzzyiC Probiotic Chews | Species named | 7.5 billion CFU (3 chews) | No | $0.27 a day |
| Nature Target Probiotics Freeze Dried Chews (Chicken) | Not named | 12 billion CFU (2 chews) | No | $0.28 a day |
| ZEBORA Probiotics Soft Chews (Chicken) | Species named | 12 billion CFU (2 chews) | No | $0.28 a day |
| Petsology Advanced Probiotics Soft Chews | Species named | 1.5 billion CFU (3 chews) | No | $0.29 a day |
| Woyamay Probiotic Chews | Not named | 3 billion CFU (3 chews) | No | $0.33 a day |
| Bark&Spark Probiotic Powder (Digestive Health) | Species named | 5 billion CFU (1 scoop) | No | $0.33 a day |
| TTLXRL Probiotics Soft Chews (Chicken) | Species named | 7.5 billion CFU (3 chews) | No | $0.34 a day |
| Nature Target 4-in-1 Probiotic Powder | Species named | 12 billion CFU (2 scoops) | No | $0.40 a day |
| PENPEN Probiotic Soft Chews (Beef) | Species named | 5.1 billion CFU (3 chews) | No | $0.43 a day |
| Wag Probiotic Daily Chews | Exact strain (GBI-30 6086) | 240 million CFU (2 chews) | No | $0.44 a day |
| Native Pet Probiotic Powder | Species named | 6 billion CFU (1 scoop) | Yes | $0.50 a day |
| Vet Promise Probiotics Gut Health Soft Chews | Species named | 3 billion CFU (3 chews) | No | $0.51 a day |
| VetriScience Extra Strength Gut Health (formerly Vetri Mega Probiotic) Capsules, and cats | Species named | 15 billion CFU (2 capsules) | Yes | $0.55 a day |
| CHEWIA Probiotics Soft Chews (Duck) | Species named | 8 billion CFU (4 chews) | No | $0.56 a day |
| VientoSeek Probiotics Soft Chews (Duck) | Species named | 6 billion CFU (2 chews) | No | $0.57 a day |
| Pet Honesty Probiotics, Gut + Immune Health Soft Chews with Digestive Enzymes, Pumpkin | Species named | 6 billion CFU (2 chews) | Yes | $0.59 a day |
| Pawzitive Pets Pre+Probiotics & Enzymes Soft Chews | Not named | 4.5 billion CFU (3 chews) | No | $0.60 a day |
| TTLXBL Probiotic Chews | Species named | 7.5 billion CFU (3 chews) | No | $0.60 a day |
| Nutramax Proviable Probiotics + Prebiotics, Chewable Tablets | Exact strain (NCIMB 30183) | 5 billion CFU (1 tablet) | No | $0.67 a day |
| Zesty Paws Daily Probiotic Bites | Species named | 6 billion CFU (2 chews) | Yes | $0.73 a day |
| Paw Balance Probiotic + Multivitamin Chews (Chicken) | Species named | 3 billion CFU (2 chews) | No | $1.00 a day |
| Native Pet GutWell Power Poop | Species named | 1 billion CFU (2 scoops) | Yes | $1.00 a day |
| Purina FortiFlora Probiotic Powder | Exact strain (SF68) | 100 million CFU (1 packet) | Yes | $1.03 a day |
| Royal Canin Probiotics Powder (S. boulardii) | Exact strain (CNCM I-1079) | 1.1 billion CFU (1 packet) | No | $1.03 a day |
| Vetoquinol Pro-Pectalin Chewable Tablets and cats | Species named | 1.5 billion CFU (2.5 tablets) | Yes | $1.25 a day |
| Vet One VetOne Advita Probiotic Nutritional (powder, 30 packets) | Species named | 200 million CFU (1 packet) | No | $1.55 a day |
| Purina Veterinary Supplements Multi Care Canine Soft Chews | Species named | 600 million CFU (3 chews) | Yes | $2.00 a day |
| Purina Veterinary Supplements FortiFlora Canine Probiotic (30 sachets) | Exact strain (SF68) | 100 million CFU (1 packet) | Yes | $2.07 a day |
| Pawfy Probiotics Soft Chews (Turkey & Bacon) | Species named | 5 billion CFU (2 chews) | Yes | $2.33 a day |
| Dinovite Probiotics for Large Dogs, Probiotic Food Topper | Species named | 300 million CFU (3 scoops) | No | $4.50 a day |
Source: Each brand's label; Amazon prices read October 28, 20265, 6
FortiFlora vs Pro Plan, FortiFlora Pro, Proviable and Royal Canin
FortiFlora vs Pro Plan. Same thing: FortiFlora is part of Purina's Pro Plan Veterinary Supplements line. The powder packet gives 100 million CFU of SF68, one a day, for $1.03 a day.2 It also comes as chewable tablets, $1.00 a day.
FortiFlora vs FortiFlora Pro. Same strain, SF68, one packet a day; Pro adds psyllium husk, a fiber that feeds gut bacteria.7 Pick Pro if you want the added fiber.
FortiFlora vs Proviable. Proviable chewable tablets give 5 billion CFU a day from 7 strains, each with a strain code, for $0.67 a day. That is 50 times FortiFlora's 100 million CFU. Proviable-DC capsules have the same 7 strains at 5 billion CFU each.8 Pick Proviable for more strains and CFU; pick FortiFlora for the lab-checked count and one packet a day. The full comparison is on FortiFlora vs Proviable.
FortiFlora vs Royal Canin. Same price, $1.03 a day, different microbe: Royal Canin's packet uses a yeast, Saccharomyces boulardii CNCM I-1079, at 1.1 billion CFU a day.9 It is the same species of yeast used in the antibiotic diarrhea trial below.10
| Product | What is in it | CFU a day | Cost a day |
|---|---|---|---|
| Purina FortiFlora Probiotic Powder | Enterococcus lactis (faecium) SF68 | 100 million CFU | $1.03 a day |
| Nutramax Proviable Probiotics + Prebiotics, Chewable Tablets | 7 strains, each with a strain code | 5 billion CFU | $0.67 a day |
| Royal Canin Probiotics Powder (S. boulardii) | Saccharomyces boulardii CNCM I-1079 | 1.1 billion CFU | $1.03 a day |
What the research says
A 2019 review of 17 dog studies found the clearest results for sudden diarrhea: guide dogs given Bifidobacterium animalis AHC7 got better in 3.9 days instead of 6.6, and kennel dogs on antibiotics given Saccharomyces boulardii had diarrhea for 2.9 days instead of 6.5.10 FortiFlora's strain, SF68, was tested in a shelter trial of 182 dogs and 217 cats; cats on SF68 had fewer bouts of diarrhea lasting two days or more (7.4% vs 20.7%).11
Using a probiotic with antibiotics
Give the probiotic at least two hours before or after the antibiotic, keep giving it through the course, and keep going for one to two weeks after.12 Cornell's canine health center calls probiotics "very safe" for a short bout of diarrhea or a stressful time, and says to stick to probiotics made for dogs.13 If the stool has blood in it, see your vet.
Questions people ask
- What is the best probiotic for dogs?
- For most dogs, Purina FortiFlora (SF68): one packet a day for any size dog, $1.03 a day, with the NASC seal. For the lowest cost, Horbäach River & Rula ProBi-Pet Digestive Aid Chewable Tablets (Horbaach), dogs and cats is $0.08 a day for a 50 lb dog. For the lowest cost with the NASC seal, Pet Naturals Daily Probiotic Soft Chews is $0.23 a day.
- What is the best probiotic for dogs with diarrhea?
- FortiFlora (SF68) is the one vets know best, at $1.03 a day. For diarrhea after antibiotics, Royal Canin's S. boulardii packet uses the same yeast species as a trial that cut diarrhea from 6.5 days to 2.9, at $1.03 a day.
- FortiFlora vs Proviable: which is better?
- Pick Proviable for more strains and CFU: 7 strains and 5 billion CFU a tablet at $0.67 a day, against FortiFlora's one strain (SF68) at 100 million CFU a packet. Pick FortiFlora for the lab-checked count and one packet a day.
- Can I give my dog a probiotic with antibiotics?
- Yes. Give it at least two hours before or after the antibiotic, keep giving it through the course, and keep going for one to two weeks after.
- Can dogs take human probiotics?
- Cornell's canine health center says to stick to probiotics made for dogs, because human probiotics are aimed at different gut bacteria.
- What is the difference between FortiFlora and FortiFlora Pro?
- Both use the SF68 strain at one packet a day. FortiFlora Pro adds psyllium husk, a fiber that feeds gut bacteria.
- How many CFU does a dog need?
- Not always more. Counts here run from 100 million CFU to 15 billion CFU a day for a 50 lb dog, and FortiFlora gives 100 million from a named strain. Look at the strain and the maker as well as the count.
Notes and sources
- Strains, CFU per serving and the dose by weight come from each brand's label, read October 2026. See how we do the math.
- The NASC seal is listed by maker, from NASC's own member list.
- For Zesty Paws' probiotic, see Is Zesty Paws good?
- Product photos come from Amazon.
- Prices checked on Amazon October 28, 2026. Published .
Sources
- Weese JS, Martin H, "Assessment of commercial probiotic bacterial contents and label accuracy," Canadian Veterinary Journal, 2011, read October 28, 2026.
- Purina Pro Plan Veterinary Supplements FortiFlora Canine Probiotic, Covetrus product listing (active ingredient: Enterococcus faecium SF68, 1x10^8 CFU), read October 28, 2026.
- Horbäach label: River & Rula ProBi-Pet Digestive Aid Chewable Tablets (Horbaach), dogs and cats, read October 2026.
- Pet Naturals label: Daily Probiotic Soft Chews, read October 2026.
- Prices: Amazon product data, read October 28, 2026. Cost per serving = listing price divided by the servings in the container.
- National Animal Supplement Council, member list (green check = may show the NASC Quality Seal), read October 28, 2026.
- Purina Australia, "PPVS FortiFlora Pro Canine 30 x 2g" (psyllium husk and SF68 per sachet, one packet a day), read October 28, 2026.
- 1800PetMeds, "Nutramax Proviable-DC" label (5 billion CFU per capsule minimum, 7 strains with NCIMB codes), read October 28, 2026.
- Royal Canin label: Probiotics Powder (S. boulardii), read October 2026.
- Jensen AP, Bjørnvad CR, "Clinical effect of probiotics in prevention or treatment of gastrointestinal disease in dogs: A systematic review," Journal of Veterinary Internal Medicine, 2019 (17 studies), read October 28, 2026.
- Bybee SN, Scorza AV, Lappin MR, "Effect of the Probiotic Enterococcus faecium SF68 on Presence of Diarrhea in Cats and Dogs Housed in an Animal Shelter," Journal of Veterinary Internal Medicine, 2011 (Colorado State University; funded by Nestlé Purina), read October 28, 2026.
- Morgan J (CVT, RVT), "Can probiotics protect the gut during antibiotic therapy?," Veterinary Practice News, August 25, 2026 (general guidelines: give probiotics at least two hours before or after antibiotics, keep giving them through the course and for one to two weeks after), read October 28, 2026.
- Cornell University College of Veterinary Medicine, Riney Canine Health Center, "Diets to boost immunity" (from the DogWatch newsletter), read October 28, 2026.
Labels for the products in the tables
- Bark&Spark: Probiotic Powder (Digestive Health).
- CHEWIA: Probiotics Soft Chews (Duck).
- Dinovite: Probiotics for Large Dogs, Probiotic Food Topper.
- Horbäach: River & Rula ProBi-Pet Digestive Aid Chewable Tablets (Horbaach), dogs and cats.
- Native Pet: GutWell Power Poop, Probiotic Powder.
- Nature Target: 4-in-1 Probiotic Powder, Probiotics Freeze Dried Chews (Chicken).
- Nusentia: Probiotic Miracle Powder.
- Nutramax: Proviable Probiotics + Prebiotics, Chewable Tablets.
- PENPEN: Probiotic Soft Chews (Beef).
- Paw Balance: Probiotic + Multivitamin Chews (Chicken).
- Pawfy: Probiotics Soft Chews (Turkey & Bacon).
- Pawzitive Pets: Pre+Probiotics & Enzymes Soft Chews.
- Pet Honesty: Probiotics, Gut + Immune Health Soft Chews with Digestive Enzymes, Pumpkin.
- Pet Naturals: Daily Probiotic Soft Chews.
- Petsology: Advanced Probiotics Soft Chews.
- Purina: FortiFlora Probiotic Powder, Veterinary Supplements FortiFlora Canine Probiotic (30 sachets), Veterinary Supplements Multi Care Canine Soft Chews.
- Royal Canin: Probiotics Powder (S. boulardii).
- SnazFirst: Probiotic Chews (Chicken).
- TTLXBL: Probiotic Chews.
- TTLXRL: Probiotics Soft Chews (Chicken).
- TzzyiC: Probiotic Chews.
- Vet One: VetOne Advita Probiotic Nutritional (powder, 30 packets).
- Vet Promise: Probiotics Gut Health Soft Chews.
- Vetoquinol: Pro-Pectalin Chewable Tablets and cats.
- VetriScience: Extra Strength Gut Health (formerly Vetri Mega Probiotic) Capsules, and cats.
- VientoSeek: Probiotics Soft Chews (Duck).
- WEALLIN: Probiotic Chews (Chicken).
- Wag: Probiotic Daily Chews.
- Woyamay: Probiotic Chews.
- ZEBORA: Probiotics Soft Chews (Chicken).
- Zesty Paws: Daily Probiotic Bites.