Our reviews are based on extensive research and, when possible, hands-on testing. Each time you make a purchase through one of our independently-chosen links, we may earn a commission. Learn more.

The 7 Best Probiotics for Cats

comments-icon 68 Comments on The 7 Best Probiotics for Cats
kate
Updated by  Kate Barrington
Share Email Pinterest Linkedin Twitter Facebook
Best Probiotics for Cats products list

Sarah Zimerman / Cats.com

The best probiotics for cats combine efficacy, quality control, and palatability. They’re made by reputable companies and grounded in the latest research. That’s why we’ve chosen FullBucket Health’s probiotic blend as the overall best probiotic supplement for cats.

Featuring a thoroughly researched probiotic strain with prebiotic and enzyme support, this supplement is intended to aid your cat’s digestive health and overall well-being.

But with limited customer reviews and a high price, this probiotic supplement isn’t for every cat. To help you find the right probiotic for your cat, we’ve included an array of the best probiotics on the market.

At a Glance: Best Probiotics for Cats in 2024

Clock
2000
hours of
research
Eye
88
brands
vetted
Check
7
features
reviewed
Star
7
top
picks
Overall Best
10.0
Picked by 25 people today!

FullBucket Health Daily Cat 

  • Synergized with prebiotics for maximum efficacy
  • Easy-to-administer powder formula
  • Well-known and popular supplement
Runner Up
9.9
Picked by 31 people today!

FERA Probiotics for Dogs and Cats

  • Contains a diverse array of probiotic strains
  • Meets the USDA’s organic standards
  • Formulated by a veterinarian
Best for Liquid
9.7
Picked by 21 people today!

Purina Pro Plan Veterinary Diets FortiFlora Probiotic Cat Supplement

  • Good for cats with low appetite
  • Contains a research-supported strain of beneficial bacteria
  • Well-known product with thousands of authentic customer reviews
Best Powder
9.8
Picked by 31 people today!

Bark and Whiskers Complete Probiotics Supplement

  • Contains 14 strains of beneficial bacteria
  • Easy-to-administer powder formula
  • Helps maintain pH balance in the colon
Best Soft Chew
9.6
Picked by 31 people today!

Pet Naturals Daily Probiotic Cat Chews

  • Easy-to-administer soft chews
  • Contains both prebiotics and probiotics
  • Resealable bag to keep the chews fresh
Best Short-Term Treatment
9.2
Picked by 31 people today!

Nutramax Proviable-DC Digestive Health Supplement

  • Individually packaged to stay fresh between doses
  • One capsule contains 5 billion CFUs
  • May help relieve occasional loose stools and digestive upset
Best Gel
9.6
Picked by 18 people today!

Benebac Plus Probiotic Pet Gel

  • Dial-a-dose syringe for easy administration
  • Ideal for kittens
  • Relatively affordable

Top Picks Explained

Do Cats Need Probiotics?

The term microbiome refers to the population of microorganisms (bacteria, viruses, protozoa, and fungi) that live inside the body and on the skin. Researchers have only scratched the surface of the human microbiome and we know even less about the feline microbiome.

The relationship between the microbiome, gastrointestinal tract, immune system, and every other part of the body is exceedingly complex. We anticipate benefits from adding extra bugs to the billions already populating the body, but we don’t know how far those benefits go.

That said, there is some scientific evidence to suggest that probiotic supplementation can be beneficial for cats with certain conditions or health concerns. Here are some examples.

Digestive Conditions

Because probiotics both promote a healthy community of microorganisms and stabilize barriers in the digestive tract, they can protect the body from inflammatory substances, help the microbiota to flourish after antibiotic therapy, and aid in recovery after digestive disturbances.

According to several controlled trials, probiotic supplementation can reduce food’s transit time through the GI tract, improve stool consistency, and increase stool frequency. This means that in addition to reducing diarrhea, probiotics can treat constipation.

Compromised Immunity

Certain genes and compounds derived from probiotics mediate immunoregulatory effects, enhancing innate immunity (the body’s first line of defense against foreign invaders) and modulating inflammation. Therefore, probiotics can help cats with immune-related diseases like allergies or infections.

Kidney Disease

In chronic kidney disease (CKD), the kidneys have a reduced ability to detoxify the body. Instead of being filtered out in the kidneys, bacteria and endotoxins (toxins released by bacteria) have no choice but to enter the gut. Theoretically, probiotic supplementation can perform a sort of “enteric dialysis”, doing in the gut what the kidneys can no longer do.

Cats with kidney disease are often given a synergized prebiotic and probiotic called Azodyl as part of their diet. Azodyl is marketed specifically for these cats and, according to some research, can help to move toxins and bacteria out of the gut and bloodstream. While Azodyl’s efficacy is unclear, there is no significant evidence that it is harmful to cats.

Dysbiosis

Antibiotics can wipe out both the good and bad bacteria in your cat’s body. Regular doses of a probiotic supplement help to rebuild the friendly populations destroyed during antibiotic therapy in cats. Probiotics can also be given in conjunction with antibiotics to help mitigate any potential negative impact on your cat’s microbiome.

Why Trust Cats.com

Over the past four years, I’ve spent a lot of time studying feline biology, primarily from a nutritional perspective. To write this piece, I dug into the topic of feline digestive health, relying on scientific publications and resources like the Cummings School of Veterinary Medicine, The American Journal of Clinical Nutrition, and the NIH’s in-depth report on probiotics.

To identify the best probiotics for cats, I examined product listings, cat health forums, and customer reviews. And because the probiotics space is plagued by fake customer reviews, I also put the reviews’ veracity to the test on FakeSpot.com.

Throughout the process, I consulted veterinary experts to learn more about the role probiotics can play in supporting digestive health and how to identify trustworthy products.

The 7 Best Probiotics for Cats

After hours of market research and in-depth testing, we’ve chosen the Daily Cat supplement from FullBucket Health as our top recommendation. Powdered for easy administration, this 4-in-1 probiotic supplement supports a healthy gut microbiome through a combination of prebiotics, probiotics, and digestive enzymes.

While Daily Cat probiotic powder is our top pick, it may not be the right choice for every cat. If your veterinarian recommends a probiotic supplement for your cat, they may also advise you to look for a particular strain (or combination of strains) of beneficial bacteria. We’ve included probiotics with a variety of formulations and formats to help you find the right fit for your cat.

#1 Overall Best: FullBucket Health Daily Cat Probiotic

FullBucket Health Daily Cat

Sarah Zimerman / Cats.com

  • Format: Powder
  • CFUs per Serving: 2.5 billion
  • Number of Strains: 1
  • Typical Cost Per Day: $0.98

Formulated for daily maintenance, this supplement is a 4-in-1 probiotic powder that supports your cat’s health by aiding in the digestion of nutrients and the formation of a healthy gut microbiome.

Each 87g tub contains about 30 servings, or a one-month supply for adult cats and a two-month supply for kittens. The formula is all-natural, made without artificial colors, flavors, or preservatives. The only inactive ingredient is flaxseed meal.

The key ingredient in this probiotic blend is microencapsulated Saccharomyces cerevisiae (S. cerevisiae) in a dosage of at least 2.5 billion CFU per serving. It’s worth noting, however, that while S. cerevisiae is listed due to restrictions on pet product labeling, the specific strain in use is Saccharomyces cerevisiae boulardii (S. boulardii). The two strains are nearly identical at the molecular level and S. boulardii is a yeast-based probiotic, the digestive benefits of which are supported by a wealth of scientific research.

In addition to probiotics, this daily supplement also contains prebiotics to support microflora balance in the gut, L-glutamine for gastrointestinal health, and digestive enzymes to promote nutrient absorption.

What We Liked:

  • Contains both prebiotics and probiotics for gut health
  • Includes digestive enzymes to boost nutrient absorption
  • Easy-to-administer powder formula
  • Microencapsulated to protect probiotics from heat and moisture

What We Didn’t Like:

  • Can be expensive if used twice daily
  • Some cats may not like the flavor

#2 Runner Up: FERA Probiotics for Dogs and Cats

FERA Probiotics for Dogs and Cats

Sarah Zimerman / Cats.com

  • Format: Powder
  • CFUs per Serving: 5 billion
  • Number of Strains: 12
  • Typical Cost Per Day: $0.48

Like our top pick, this probiotic supplement from FERA Pet Organics comes in an easy-to-administer powdered formula. Each 2.5-ounce jar contains 60 servings for cats weighing 5 to 15 pounds. The flavorless formula is free from grains, dairy, and artificial additives.

In addition to being a well-rounded probiotic supplement with a diverse mix of beneficial bacteria and yeast, this supplement has a couple of certifications that set it apart from the rest. It’s USDA-certified organic and has earned the NASC’s quality seal. The formula was created by a veterinarian.

Each serving gives your cat 5 billion CFUs of the following twelve strains:

  • Lactobacillus acidophilus
  • Lactobacillus casei
  • Saccharomyces boulardii
  • Lactobacillus plantarum
  • Bifidobacterium infantis
  • Lactobacillus bulgaricus
  • Bifidobacterium bifidum
  • Bifidobacterium longum
  • Enterococcus faecium
  • Lactobacillus brevis
  • Lactobacillus rhamnosus
  • Streptococcus thermophilus

The probiotics are synergized with prebiotics for optimal performance.

What We Liked:

  • Contains a diverse array of probiotic strains
  • Meets the USDA’s organic standards
  • Formulated by a veterinarian
  • Synergized with probiotics FOS and inulin

What We Didn’t Like:

  • Flavorless formula may be less appealing than other options

#3 Best Liquid Probiotic: Purina Pro Plan Veterinary Diets FortiFlora Probiotic Cat Supplement

Purina Pro Plan Veterinary Diets FortiFlora Probiotic Cat Supplement

Sarah Zimerman / Cats.com

  • Format: Powder
  • CFUs per Serving: 100 million
  • Number of Strains: 1
  • Typical Cost Per Day: $1.03

This best-selling probiotic supplement is commonly recommended by veterinarians and is probably the first product people think of when discussing probiotics made for cats. Fortiflora is different from other probiotics in several respects.

First of all, it doesn’t contain the multiple strains that we typically look for. Instead, each sachet contains 100 million CFUs of a single species of bacteria—Enterococcus faecium. Because E. faecium has well-known benefits for cats and dogs suffering from digestive issues, it is recommended for cats with diarrhea or other digestive problems. It can also promote healthy immune function.

Also, this probiotic is made with hydrolyzed animal tissue, a crazy-concentrated flavor additive that drives cats wild. For this reason, Fortiflora is well-known as an appetite stimulant and widely used among cats with kidney disease and consequent loss of appetite.

Some rail against animal digest, saying that it’s made from animal ingredients of unknown quality. This is true—we don’t know what animals went into this flavor juice. There’s a chance that the animals used aren’t of the quality you’d prefer. However, you need not worry that the animal digest will irritate your cat’s allergies. Hydrolysis renders animal proteins non-allergenic, so that’s not a concern.

What We Liked:

  • Good for inappetent cats
  • Contains a well-documented and well-researched strain of beneficial bacteria
  • A well-known product with thousands of authentic customer reviews
  • Comes in easy-to-serve packets of powder

What We Didn’t Like:

  • Expensive
  • Contains just one probiotic species
  • Relatively low CFUs

#4 Best Powdered Probiotic: Bark and Whiskers Complete Probiotics Supplement

Bark and Whiskers Complete Probiotics Supplement

Sarah Zimerman / Cats.com

  • Format: Powder
  • CFUs per Serving: 38 billion
  • Number of Strains: 14
  • Typical Cost Per Day: $0.33

Powdered probiotic supplements are easy to administer and, because your cat consumes them alongside their food, delivery of each dose will be perfectly timed. This Bark and Whiskers formula contains 14 carefully selected strains of beneficial bacteria to promote healthy digestion and immune system function.

Each scoop of this probiotic powder contains 38 billion CFU of acid-resistant beneficial bacteria. By promoting a healthy gut microbiome, these bacteria support the production of enzymes and lactic acid in the digestive tract which are essential for maintaining normal colon pH balance and regular digestion.

Each scoop gives your cat 38 billion CFUs of the following 15 strains:

  • Bifidobacterium lactis
  • Lactobacillus acidophilus
  • Bifidobacterium longum
  • Bifidobacterium bifidum
  • Lactobacillus casei
  • Lactobacillus plantarum
  • Saccharomyces boulardii
  • Bifidobacterium breve
  • Streptococcus thermophilus
  • Saccharomyces boulardii
  • Bifidobacterium animalis
  • Enterococcus faecium
  • Lactobacillus rhamnosus
  • Lactobacillus bulgaricus
  • Bacillus coagulans

Bark and Whiskers recommends a ½-scoop serving for daily maintenance, though some cats may require a full scoop for therapeutic purposes. Ask your veterinarian for dosing advice.

What We Liked:

  • Contains 15 strains of beneficial bacteria
  • Easy-to-administer powder formula
  • Helps maintain pH balance in the colon

What We Didn’t Like:

  • Some cats don’t seem to like the flavor

#5 Best Probiotic Soft Chew: Pet Naturals Daily Probiotic Cat Chews

Pet Naturals Daily Probiotic Cat Chews

Sarah Zimerman / Cats.com

  • Format: Soft chew
  • CFUs per Serving: 120 million
  • Number of Strains: 1
  • Typical Cost Per Day: $0.20

Probiotic soft chews don’t typically contain as many CFUs per serving as powdered supplements but they’re a convenient alternative for cats who won’t accept powder. These duck-flavored soft chews from Pet Naturals contain 120 million CFUs of Bacillus coagulans in each 1-piece serving.

In addition to probiotics, these soft chews contain prebiotic fibers to help support healthy gut flora. It’s worth noting that high-fiber plant ingredients like oat flour, rice flour, rye flour, and barley flour add to the carb content of the chews, but the serving size is so small that it won’t contribute significantly to your cat’s overall diet.

The recommended serving size for this product is one 1.2-gram soft chew per day.

What We Liked:

  • Easy-to-administer soft chew
  • Contains probiotics and prebiotics
  • Affordably priced around $0.20 per chew

What We Didn’t Like:

  • Lower in CFUs than powdered supplements
  • High carbohydrate content

#6 Best Short-Term Probiotic: Nutramax Proviable-DC Digestive Health Supplement

Nutramax Proviable-DC Digestive Health Supplement

Sarah Zimerman / Cats.com

  • Format: Capsules
  • CFUs per Serving: 5 billion
  • Number of Strains: 7
  • Typical Cost per Day: $0.50/day

Probiotic supplements for cats can help manage the symptoms of chronic digestive issues but some cats simply don’t need daily, long-term treatment. A short-term course of probiotics can help relieve digestive upset linked to dietary changes, stress, or occasional loose stool. These probiotic capsules are individually packaged so they stay fresh until you need them.

The following species appear in the capsules:

  • Bifidobacterium bifidum
  • Enterococcus faecium
  • Enterococcus thermophilus
  • Lactobacillus acidophilus
  • Lactobacillus bulgaricus
  • Lactobacillus casei
  • Lactobacillus plantarum

Each capsule contains 5 billion CFUs to help restore your cat’s healthy intestinal balance. The product also contains pectin and kaolin to help firm up loose stool and soothe the digestive tract. To administer, simply open the capsule and sprinkle the powder over your cat’s food.

What We Liked:

  • Individually packaged to stay fresh between uses
  • One capsule contains 5 billion CFUs
  • May help relieve occasional loose stools and digestive upset

What We Didn’t Like:

  • Some cats seem to dislike the flavor

#7 Best Gel Probiotic: Benebac Plus Probiotic Pet Gel

Benebac Plus Probiotic Pet Gel

Sarah Zimerman / Cats.com

  • Format: Gel
  • CFUs per Serving: 20 million/g
  • Number of Strains: 7
  • Typical Cost Per Day: $0.63/g

This well-known probiotic gel contains seven beneficial microorganisms. Each gram of gel contains 20 million CFUs of viable bacteria. It’s recommended that adult cats take 1 gram for every 10 pounds of body weight.

This probiotic gel contains seven species of beneficial bacteria:

  • Lactobacillus casei
  • Lactobacillus fermentum
  • Lactobacillus acidophilus
  • Lactobacillus plantarum
  • Enterococcus faecium
  • Bifidobacterium bifidum
  • Pediococcus acidilactici

The gel syringe is a good choice for cats who cannot or will not take probiotics in their food, like kittens who are bottle feeding. Because these kittens don’t receive an inoculation of bacteria from their mother’s milk, a probiotic supplement can help support the growth of good GI bacteria.

The gel is guaranteed viable for 1 year after the date of manufacture printed on the package.

What We Liked:

  • Ideal for kittens
  • Dial-a-dose syringes are easy to use
  • Relatively affordable
  • Made with the prebiotic FOS
  • Well-known and respected

What We Didn’t Like:

  • Contains artificial color
  • Some cats won’t like the syringe application
  • Relatively low CFUs

What to Look for When Shopping for Probiotics for Cats

It’s always important to do some research before purchasing a product for your cat but especially essential when it comes to supplements. Supplements aren’t held to the same regulatory scrutiny as food products and health claims are difficult to verify. This is particularly true for probiotics.

When Labdoor performed microbiological testing on 37 of the United States’ best-selling probiotics, they found that: “Total viable bacteria ranged from 0% to 308% of the products’ stated label claims.”

Even with in-depth research, there’s no guarantee a probiotic will work for every cat. But careful selection will improve the chances of success. Here are some features to look for when shopping for probiotics for cats.

Research-Backed Bacterial Strains

Remember that you’re introducing living organisms to your cat’s inner ecosystem, and like any other ecosystem, the microbiome is competitive. If you attempt to colonize it with too many species, competition and dilution could result.

It’s best to stick to bacterial strains with strong scientific backing. Check the active ingredients on the product label and look for names that start with Lactobacillus, Bifidobacterium, or Bacillus. These are some of the most highly researched probiotics.

Colony-Forming Units (CFUs)

Don’t underestimate the importance of probiotic viability. Colony-forming units (CFUs) are a measure of probiotic viability, indicating the number of live and active bacteria per probiotic dose. Look for a probiotic that delivers at least 1 billion CFUs per dose. And pay attention to the serving size—the CFUs may be calculated for a larger dose than what is recommended for cats.

Palatable and Easy to Feed

Probiotics come in a variety of forms including pills, powders, and liquids. If your cat doesn’t like taking pills, a powder or liquid you can add to their food might be a better option. Think about flavoring as well—many probiotics are flavorless but flavor additives can make them more palatable.

Pet probiotics are often flavored with animal digest, which is made from hydrolyzed animal tissue and is incredibly tasty to cats. If you’ve ever given your cat a Temptations treat, you’ll know how much cats love this flavor additive.

Safe Manufacture and Storage

Information on a product label is only worth so much—it’s important to fact-check them to determine whether the manufacturer of a product is trustworthy or not. Human-grade products and those with the National Animal Supplement Council (NASC) quality seal may be more likely to live up to the promises on the label.

Unless handled with care, the rigors of storage and transport will kill live probiotics before they reach their would-be home inside your cat’s body. While some—including yeast and freeze-dried probiotics in tablets or capsules—stay fresh on the shelf, other probiotics require refrigeration. If you buy a probiotic that needs to be refrigerated, make sure it’s stored under refrigeration and shipped as quickly as possible.

Verified Customer Reviews

Whether health supplements are peddled for cats or humans, their purported benefits are usually vague, making those benefits easy to exaggerate and hard to refute. And because probiotics are so little understood but so full of potential, it’s easy to make bold claims without pushback.

Overly positive reviews may be a reflection of a great-quality product, but they could be deceptive. Before adding any product to our list of top probiotics, I checked its trust score on FakeSpot to ensure that the positive reviews were trustworthy. This is a tactic you can use when doing your own shopping.

Frequently Asked Questions

Do vets recommend probiotics for cats?

It depends. While healthy cats may not require a daily probiotic, cats with digestive problems may benefit from a daily probiotic. If your cat is experiencing diarrhea, constipation, or digestive upset, talk to your veterinarian to determine whether a probiotic supplement might be appropriate.

Can cats use human probiotics?

Buying probiotics for pets doesn’t mean that you’re getting a mix of strains that are targeted to the feline microbiome, because people don’t know enough about the feline microbiome to create such a supplement.

Therefore, feline-specific probiotics aren’t necessarily better for your cat than a supplement packaged for humans. In fact, human-oriented products often give you better quality for a lower price. Cat-specific probiotics, however, have an advantage in the flavor department.

How much should you give your cat?

There are no official dosing guidelines for cats, but it’s recommended that you give your cat a probiotic supplement guaranteed at between 1 billion and 5 billion CFUs each day.

small mallory photo

About Mallory Crusta

Mallory is the Head of Content at Cats.com and an NAVC-certified Pet Nutrition Coach. Having produced and managed multimedia content across several pet-related domains, Mallory is dedicated to ensuring that the information on Cats.com is accurate, clear, and engaging. When she’s not reviewing pet products or editing content, Mallory enjoys skiing, hiking, and trying out new recipes in the kitchen. She has two cats, Wessie and Forest.

68 thoughts on “The 7 Best Probiotics for Cats”

+ Add Comment

Leave a Reply

Your email address will not be published. Required fields are marked *

    1. Mallory Crusta

      Hi Sara,

      Any of the probiotics on this list could help your cat with IBD. You’ll probably want to go with the powdered probiotics or pearls rather than the Benebac gel, since it doesn’t sound like your cat is otherwise sick or inappetent. Other than that, they’re all good options.

      From what I’ve gathered, IBD cats benefit from eating as close to a prey model diet as possible. This may mean a raw diet, a home cooked diet, or a simple meat-based canned food.

      If you haven’t already, I highly recommend reading our article on the best cat food for IBD:

      https://cats.com/best-cat-food-for-ibd

      It goes into depth on the relationship between IBD and diet and lists our top 5 foods for cats with this condition.

      Hope this helps!

      – Mallory

      Reply
      1. Gilda Cummings

        Hi I have a cat with IBD who suffers from vomiting and constipation, which probiotic would work best to treat his condition?
        He has been taking Petdophilus for almost two years and it worked great to keep him regular; but now he’s starting to get constipated again.

        Reply
  1. Kim

    My cat has idiopathic hypercalcaemia. Would taking probiotics help reduce calcium levels in her blood? If yes, which brand would be best choice?
    Thanks
    Kim

    Reply
    1. Mallory Crusta

      Hi Kim,

      Hypercalcemia isn’t something I’m very familiar with, but I did a little research. It doesn’t appear that probiotic supplementation can help much, though I did find a couple mentions of probiotics having the potential to promote healthy vitamin K2 synthesis. Vitamin K2 carboxylates proteins that help to bind calcium to the bone and leads it away from the blood and other unwanted areas of the body. Vitamin K2 is synthesized by the body’s intestinal flora. If that flora is imbalanced, vitamin K2 production will be impacted. A wide-spectrum probiotic might help to balance the gut flora and promote healthy vitamin K2 production. Because it has a wide variety of probiotic strains, the Hyperbiotics probiotic listed as our top pick should serve well for this purpose.

      Overall, however, probiotic supplementation doesn’t appear to be a promising treatment for hypercalcemia at this time. A veterinarian can probably give you more advice and help you to find a treatment plan that works for your cat.

      Hope this helped and that you find more answers soon!

      Best,

      Mallory

      Reply
  2. Kim

    Thanks Mallory.
    What about digestive enzymes? I understand that fibre in this is better for cats than plant fibre in Metamucil or bene fibre. My vet has only recommended putting more fibre in my cat’s diet but this hasn’t helped. Then I read about animal fibre from the fur, feathers, etc. of natural prey is better for cats. Ant help you can provide would be appreciated.
    Kim

    Reply
    1. Mallory Crusta

      Hi Kim,

      I haven’t heard of any connection between digestive enzymes and hypercalcemia. They might help and they might not. People can’t agree on what supplemental enzymes do for digestion, much less calcium absorption.

      As you mentioned, fiber like that found in Metamucil or Benefiber isn’t a natural part of the feline diet. A cat’s natural diet is around 0.55% fiber, and almost all of it comes from the GI tracts of their prey.

      Feathers, fur, cartilage, etc approximate fiber in the sense that they’re fermentable and have some of the same effects as fermentable fiber, but they aren’t true fiber and function differently in the intestine. How, exactly, does “animal fiber” affect a carnivore’s health and how does it compare to plant fiber? Again, no one really knows! The benefits of fermentable animal tissues are exciting and interesting, but also under-researched and not very well understood.

      While some cats have success with high-fiber diets to control hypercalcemia, it’s unclear whether or not a diet containing indigestible animal tissues will produce the same results. Since your cat hasn’t benefitted from the added fiber so far, added animal-sourced fiber substitutes might not be the answer, either.

      All this being said, has your veterinarian talked to you about the acidity of your cat’s diet?

      Apparently, feline hypercalcemia wasn’t reported until 1999, after acidifiers became popular as a struvite crystal preventative.

      Commercial cat food has historically been too alkaline, meaning that cats tended to develop struvite urinary crystals. Cat food manufacturers realized this and started adding acidifiers like DL-methionine, phosphoric acid, and ammonium chloride. Struvite crystals became less common, but cases of calcium oxalate crystals—which form in an overly acidic environment—started cropping up more and more. Guess what also became more common? Hypercalcemia.

      Avoiding acidifiers may help. You might also want to control levels of vitamin D and calcium and avoid any magnesium-restricted diets. All of these special requirements may mean that you’ll need to opt for a specially-balanced homemade diet, preferably formulated by a trusted veterinary nutritionist.

      If you haven’t already, you should read this article from endocrine vet Dr. Mark E. Peterson:

      https://endocrinevet.blogspot.com/2012/11/nutritional-management-of-idiopathic.html

      The article goes over the pros and cons of several nutritional management plans and concludes with Dr. Peterson’s preferred diet plan for cats with hypercalcemia.

      Hope this was helpful! Please let us know if you have any more questions.

      Take care,

      Mallory

      Reply
  3. Anne Rettie

    Hi Mallory! Thanks for your great article! We will definitely go with your recommendations. One question I haven’t been able to get answered, though, is why the better varieties of human probiotics need to be refrigerated and those for pets don’t? I’ve always assumed the refrigeration was for improved viability, but curious as to why this doesn’t come up as a topic in animal probiotics. …Anne

    Reply
    1. Mallory Crusta

      Anne, that’s a great observation.

      I had to double-check to see how the recommended brands approach the refrigeration issue. While some of the products on this list recommend refrigeration after opening (like Probiotic Miracle), the others state that it’s not necessary. Hyperbiotics even says they use “patented technology” to make refrigeration unnecessary. Interesting.

      I think there are a few factors playing into this. One is that some types of probiotic supplements don’t appear to require refrigeration. These include freeze-dried products, those in blister packs, and certain spore-forming bacteria or probiotic yeast. They’re not better or worse than any other probiotics—they just don’t need refrigeration.

      On top of that variability is the fact that people don’t yet understand exactly how probiotics affect pets and which ones might be beneficial. Pet probiotics are not standardized or well-understood and that lack of understanding means manufacturers can get away with a lot. Though it appears that all the companies making the products in this article are well aware of the importance of refrigeration for the viability of some strains, others might not be.

      At any rate, thank you for mentioning the refrigeration issue! I’ll have to address it next time I write about probiotics for cats.

      Best,

      Mallory

      Reply
    1. Mallory Crusta

      Hey Julie,

      You don’t mention what your cat is allergic to, but I’m thinking that ProGut paste should be fine. It doesn’t appear to contain any common allergens or irritants and furthermore, probiotics are a great choice for cats with allergies. They may help to soothe GI upset and improve overall health. If you still have any worries, consult your veterinarian before trying any new supplement.

      Hope this answers your question!

      Best,

      Mallory

      Reply
  4. Michelle Macari

    Hi Mallory and thank you for this post. I have a young cat that had Giardia when I adopted him, but was not told. It took just over 2 months to get him in the clear. He still has bad farts and poop. And my 9yr old princess has been throwing up (hairballs, I think. She is a Maine Coon) and she also has more “messy” poops than she or I care for…which sometimes lands her in the bath tub. Then I have Bob marley (1.5 yr old), whose poop actually sometimes gets “stuck” on the way out. And I will find a random marble as I walk down the hall. Yuk
    I purchased the NOW Saccharomyces boulardii after reading this post but am not sure what to do with it. Do I sprinkle half capsule in each food bowl twice a day, once a day, or does it need to be mixed with water and given orally?
    I am hoping this product can help noirmalize everyone’s gut flora/biome.

    Thank you in advance!!!
    Eglantine, Bob Marley & Mazarine and myself.

    Reply
    1. small mallory photoMallory Crusta Post author

      Hi Alexander, thank you for sharing this article! When paired with a species-appropriate diet that is made without excessive fiber, I believe that a probiotic supplement containing FOS or cellulose should be acceptable. That said, I would recommend discussing this matter with your veterinarian.

      Reply
  5. Lorena

    Hi. My 9 month all abyssinian was diagnosed with trichomonia and has had chronic diarrhoea for the past 3 moths. Which probiotic would you recommend

    Reply
    1. small mallory photoMallory Crusta Post author

      Hi Lorena, it’s really difficult to say! S.boulardii is known for being very helpful for diarrhea, but you may want to use it in conjunction with another probiotic supplement for additional benefits. You might be able to get more help in the All About Cats community: https://cats.com/community

      Reply
  6. Cece

    Hi Mallory,
    My house mates cat gets crystals. I’m not sure what kind. He’s about 3years old. He’s been on Hills CD cat food. He hasn’t gotten any crystals since. He’s also on amyltriptoline for stress.

    He’s long haired and grooms himself a lot. A bit obsessively. He gets big hairballs which he eats less poops less and stretches a lot before eating when he’s brewing big hairballs.

    He also needs a lot of coaxing to eat. He won’t eat unless we stand with him and start off by brushing him. But if he’s passed big hairballs he will eat well.

    We brush him daily, my housemate got a furminator brush. He loves being brushed.

    He gets good attention, loves to play on his own and with us.

    I noticed he’s also passing some gas. Quietly. So, I’ve only notice when he’s sitting next to me for a while.

    I thought a probiotic might be good for him and maybe a probiotic + digestive enzyme combo. I was hoping it would
    I don’t know if probiotics and or digestive enzymes are ok for cats who’ve had urinary crystals?

    He had crystals a couple of times. There were a lot of changes in his environment and it rained much more than usual. Plus, his fountain water wasn’t cleaned regularly, he was also eating several types of bad foods and snacks and his schedule was all over the place. He was on two or three types of petroleum based hairball formulas.

    ALL of those issues have been taken care of. (we have acclimated him to the rain sounds + it didn’t rain much this year.).
    He’s only on Hills CD urinary + stress food. No snacks. He gets a little bit of yogurt every once in a while which may help with hairballs (hard to tell). He is not on a hairball product.
    I was hoping that a probiotic alone or a combination probiotic digestive enzyme products would help with the hairballs, gas and that would help with him being less stressed about eating.
    Can you tell me if it’s ok for a cat that get crystals to have probiotics and/or digestive enzymes? (I don’t know the type of crystals) .
    Can you can recommend a probiotic digestive enzyme product that is affordable? I saw the article about 10 best probiotics.
    Thank you!
    Cece

    Reply
    1. small mallory photoMallory Crusta Post author

      Hi Cece, thank you for commenting! Yes, cats who are prone to crystals can safely take probiotics and digestive enzymes. I am thinking that a broad-spectrum probiotic would likely be the best fit for this cat. As for an affordable option, perhaps the Hyperbiotics PRO-PETS probiotic listed as our second recommendation in the article you read. This provides a mix of strains, is relatively affordable at about $0.38 per day—assuming that you’re giving him one capsule per day. Hope this helps!

      Reply
  7. Cece

    Hi Mallory,
    Thank you so much. Im grateful for the information. Do you mean that the probiotic alone is sufficient and wouldn’t need a combination formula with digestive enzymes as well, for the hairballs?

    Reply
  8. Mary Ann

    My ragamuffin has the worst infection in her toes my vet has seen in 40 years. She has had it for many months and nothing has worked to cure it so far. He said her immune system is very low and needs to be on probiotics in the billions to help build it back up. Which probiotic would you recommend for this sweet girl?

    Reply
    1. small mallory photoMallory Crusta Post author

      Hi Mary Ann, I would first think about addressing why your cat’s immune system is so low, then look into any top-rated probiotic supplement. The Nom Nom probiotic is a good option with 20 billion CFUs per serving.

      Reply
    1. Christine

      Hi Mallory! Thank you for such an informative article. My cat was very sick last week and the vet had her on a course of antibiotics. She’s thankfully all back to normal so I want to work on restoring her gut biome a bit. I was looking at the options you gave from Now Foods (Somehow I already had the S Boulardii saved to my wish list and forgot all about it!). I was wondering why you recommend the acidophilus & bifidus, which has 3 strains, over their other acidophilus mix, which has 6?

      For comparison, Acidophilus & Bifidus contains:
      Lactobacillus acidophilus 4.0 Billion CFU
      Bifidobacterium lactis 3.2 Billion CFU
      Bifidobacterium longum 0.8 Billion CFU

      The 4×6 mix contains:
      Lactobacillus acidophilus 2 Billion CFU
      Bifidobacterium lactis 1.2 Billion CFU
      Bifidobacterium longum 200 Million CFU
      Streptocous thermophilus 200 Million CFU
      Lactobacillus bulgaricus 200 Million CFU
      Lactobacillus paracasei 200 Million CFU

      The additional strains appear to be in some of your recommended supplements. Is it unwise to introduce too many strains at once?

      Also, I noticed it states on both ingredient lists:
      “Contains milk. Note for those highly sensitive to milk protein: This product may contain minute amounts of casein.” Is this something to be concerned about?

      Thanks!!

      Reply
      1. small mallory photoMallory Crusta Post author

        Hi Christine, apologies for the late reply! Looking into it again, I think you may be better off using the 4×6 blend rather the one originally recommended in this article. Especially in the case of antibiotic treatment, a diverse probiotic supplement offering a wide variety of bacteria is the best choice. Regarding the casein, the amount should be trivial enough that it would not present an issue for your cat.

        Reply
  9. Mary

    Is it ok to give my cats probiotics or prebiotics if no digestive issues. They all have dull fur and dander. would this be something to look into?

    Reply
    1. small mallory photoMallory Crusta Post author

      Absolutely! While we don’t fully understand the extent to which it does, we know that the gut microbiome affects whole-body health. Along with good diet and addressing any health issues, the addition of prebiotics and probiotics could help your cats’ coat health a lot.

      Reply
  10. Sheereen

    This is an awesome article! Been searching for this! My cat has constant occurrence of UTI, all of which triggered by an infection of e-coli bacteria. I did read that probiotics could help with harmful bacteria like e-coli in the gut and could also help with UTI. I’m wondering which is the best probiotics in the list that would help?

    Reply
    1. small mallory photoMallory Crusta Post author

      In humans, Lactobacillus species have been identified as having the most promise for urinary tract infections. The Hyperbiotics PRO-Pets – A Probiotic for Dogs & Cats listed here contains multiple strains that have shown the most promise in this area.

      Reply
  11. Alice

    Hi Mallory, Thanks for this helpful article. My cat is getting large rash spots on her head, in front of and inside her ears and above her eyes that she scratches until they bleed. They last for a few weeks or so and go away then come back. I recently changed her food to a Chewy all meat food and dry to one with much less useless filler but she’s still getting the rash. I had been giving her a probiotic chew from Meijer grocery but haven’t been able to get it anymore, don’t know why. I don’t actually know if they were doing any good but I don’t remember her getting this horrible rash then. Do you have any idea what is causing it? Can send pictures if helpful Thanks

    Reply
    1. small mallory photoMallory Crusta Post author

      Hi Alice, thanks for the email, and I apologize for the delayed response! I’d recommend seeing a veterinarian to learn more about what’s causing the rash. Identifying the underlying cause is your first step towards treating it correctly. In the meantime, I would take notes on everything that changed around the time that she started getting the rash—environmental allergies are a possible cause here, as is a flea infestation.

      Reply
      1. Alice

        Thanks for your reply. I do think it’s some kind of allergy, it’s definitely not fleas. I was just hoping you might have run across this before.

        Reply
  12. Archie

    Hello! I can’t see many references to encapsulation in the products listed. Because cats stomachs are so acedic I have studied that a probiotic needs to be encapsulated to be effective. Any thoughts on this?
    I’m looking for a good encapsulated probiotic. I’ve been using the NOW foods recommendation.

    Reply
    1. small mallory photoMallory Crusta Post author

      Hello Archie, you’re right; it does appear that encapsulation increases the survival rates of these bacteria, but there don’t seem to be many pet probiotics featuring this. While marketed for humans, this product contains several well-known strains that seem to have benefits for feline health.

      Reply
  13. Marni Velick

    Hello,
    I am struggling to give my cat a probiotic. I read here that I can give him a human product, but how would I administer it? If it comes in a capsule, would I have to dump the powder from the capsule into his food? He is an EXTREMELY picky eater, and I’m worried he would notice.

    He has IBD (diarrhea/vomiting issues) early-stage kidney disease. The main reason I want to give him a probiotic is to help him with his frequent diarrhea. The problem is that he notices if I sprinkle the powder on his food, and refuses to eat it. He loves treats, so I tried the probiotic chews, but he wouldn’t go near those either. I’m desperate, please help!

    Reply
    1. small mallory photoMallory Crusta Post author

      Hi Marni, it depends on the product. Some are timed-release products with an enteric coating intended to help the beneficial organisms get where they need to be, and these are best given as pills. Naturally, that’s not a fun prospect, and pilling a cat is quite difficult. Alternatively, you may be able to “trick” your cat into eating the probiotic by mixing it into something extremely palatable. I’ve had success feeding my cat a probiotic powder mixed into meat-based baby food. This may work for you as well. Alternatively, you may be able to administer a probiotic paste or mix up the probiotic powder with something tasty, then squirt it into your cat’s mouth with a syringe. Hope this helps!

      Reply
  14. Elle Dee

    Your overview says Nom Nom is the overall best probiotic. But you have Full Bucket listed as that and Nom Nom isn’t even on the list. Why is that? So what’s the overall best? A

    Reply
  15. Elle Dee

    Your overview says Nom Nom is the overall best probiotic. But you have Full Bucket listed as that and Nom Nom isn’t even on the list. Why is that? So what’s the overall best?

    Reply
      1. Emily Wayts

        Thanks for the reply! I see a lot of people use “feline” branded fiber supplements and I wasn’t sure if I should stick with it along with a probiotic! I have a Bengal and the Benefiber definitely keeps her regular. If my Bengal isn’t having any concerning gut issues, would it be beneficial to add a probiotic?

        Reply
        1. small mallory photoMallory Crusta Post author

          Maybe; the benefits of probiotics aren’t really that well understood, but it appears that they can have wide-ranging benefits that go beyond the gut. You can try it, but I wouldn’t say it’s necessary.

          Reply
  16. Madison Elliott

    Hello, I have a 9 month old kitten who has very loose stools. He had to get de-wormed for a parasite but afterwards he seemed fine. Then randomly he started having the loose stools again. What would be the best one for him? I have not changed his food, so I am unsure what to do.

    Reply
  17. Nina

    Hi, I was giving my ibd cat #8 saccharomyces boulardii from now food. But I am also giving other product with e.faecium and this also contains prebiotics. I’m a bit worried if there’s too much prebiotic for daily basis. Does it seem to be okay if I changed the now food saccharomyces boulardii product to https://www.amazon.com/gp/aw/d/B00JK30A1M/
    this product? It seems like it doesn’t have any prebiotic or fillers in it.
    Thanks.

    Reply
    1. small mallory photoMallory Crusta Post author

      Hi Nina! That’s an excellent question, and I’m afraid I don’t have a really good answer to it. Two products containing prebiotics should not be harmful, especially if your cat’s already eating a lower-fiber food. Remember that fiber content in a cat’s diet can vary quite widely, and there is no established maximum (or minimum) amount, so I can’t tell you how much is too much.

      Reply
  18. Tony Stack

    The only cat probiotics that Walmart sells seems to be a product called Pure Balance Pro + Probiotic Care. Any opinion on that one? Because that’s the one I bought.

    Do you know if it’s good? Bad? Anything?

    Reply
    1. small mallory photoMallory Crusta Post author

      Hi Tony! My apologies for the late reply! The CFUs in that product are pretty low, so I might consider trying one of the human probiotics at Walmart, which will give your cat much higher doses of beneficial bacteria.

      Reply
  19. KristinC

    Hi! The text of your article mentions “Nom Nom” as the best probiotic for cats. However it’s not in this list at all. Has this changed since the article was originally published? Just wondering if Nom Nom is no longer recommended. Thanks.

    Reply
    1. small mallory photoMallory Crusta Post author

      Hi there! Thanks for catching that—we missed it while updating the article. Will correct it now. As for the probiotic, they have discontinued their probiotic for cats, and their dog probiotic is not recommended for use in cats. From what I can tell, there’s nothing in it that would be unacceptable for a cat, but you may want to consult your veterinarian to confirm.

      Reply
  20. Sofia

    Hi! I’d love to get some help understanding what bacterial strains seem to be the most effective. I’m a little confused with the recommended human probiotics (At the end of the video linked in this article, Dr. Pendergrass recommends against human probiotics). In a 2022 review by Lee et al. (J Anim Sci Technol.), the authors mention evidence supporting the efficacy of L. acidophilus DSM13241 and E. faecium SF68, while Bifidobacterium seemed less important in cats and more important in dogs. The human probiotics recommended in this article (NOW acidophilus 8 billion) contain Lactobacillus acidophilus (La-14), Bifidobacterium lactis (BI-04), and Bifidobacterium longum (BI-05). How different are L. acidophilus DSM13241 and Lactobacillus acidophilus (La-14)? Do you still think human probiotics would be effective in cats? Do you have any recommendations for resources where I could learn more about cat probiotics (books, papers, lectures)? Sorry for the multiple questions, I went down a google rabbit hole. Thank you!

    Reply
    1. small mallory photoMallory Crusta Post author

      Hi Sofia, really sorry it’s taken me so long to get back to you on this! These are all excellent questions, and really, it sounds like this article needs to be updated to reflect the new information available.

      For more research, here are a few papers done on probiotics in cats—you may have already seen some of these:

      https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9962843/
      https://www.dvm360.com/view/clinical-and-research-experiences-with-probiotics-cats-sponsored-nestl-purina
      https://europepmc.org/article/med/35530406

      Reply
  21. Lonni

    After discussing my cat’s recently discovered trichomoniasis with my vet, I feel afraid to give my cat Ronidazole for this parasitic infection. My vet was also not directly with Ronidazole treatment but did not suggest an alternative.
    Would any of the pre or probiotics mentioned in your very helpful article help my senior cat with his diarrhea?
    He acts fine, cuddly, eats, playful. He is also being treated for hyperthyroidism, which is under control.

    Reply
  22. Michelle Moore

    I have a 16 year old chronically constipated cat, vet thought megacolon but specialist says not megacolon but offered no other explanation. What pre/probiotic is best for constipation?

    Reply