The Benefits Of Probiotics For Dogs According to Research - Natural Dog Supplements and Superfoods by Fetched

The Benefits Of Probiotics For Dogs According to Research

by Tudor Nikolas on Aug 12, 2023.

As a dog nutritionist, I have noticed the rapidly growing interest in probiotics for dogs. This follows on from the popularity of probiotics in humans.

Research has shown that gut bacteria are generally responsible for a lot more of our body's function than we realise.

Recent research has described how the gut microbiota are able to profoundly influence our brain function through direct communication. This means that the balance between good and bad gut bacterial colonisation has a profound effect on our mental and physical wellbeing.

Just like in humans, the  introduction of probiotics in a dog's diet can be a beneficial step in maintaining their gastrointestinal health, improving immune function, and more.

Let's explore some clear benefits of probiotics for dogs and how to introduce them into their diet.

What are Probiotics?

Probiotics are live, beneficial bacteria/ yeast that are naturally found in the gastrointestinal tract of humans and other animals, including dogs.

Their role is to maintain the balance of the gut flora and support the living body in a variety of ways.

The concept of probiotics is rooted in the understanding that not all bacteria are harmful. The good bacteria should eliminate the extra bad bacteria to keep the status quo in check.

By taking probiotics you are therefore adding extra "good bacteria" to the gut flora, helping it do its job well.


Different Types of Probiotic Bacteria and Their Classification

Bacteria used in probiotics can be classified into different genera, species, and strains.

The most common genera include Bacillus Velezensis (also known as Bacillus subtilis), Lactobacillus and Bifidobacterium, each containing various species and strains.

Some of the common good bacteria found in the gut microbiome of dogs includes:

Genus and Species Explanation Benefits for Dogs
Bacillus subtilis C-3102)/ Bacillus Velezensis Stimulates Lactobacillus increase and reduces bad E. Coli & Salmonella (*) Healthier gut microbiome and helps eliminate the harmful bacteria
Lactobacillus acidophilus Commonly found in the gut, helps in digestion and may contribute to oral health Aids in nutrient absorption, combats diarrhoea and prevents bad breath
Lactobacillus rhamnosus Known for its resilience and stability in the gut. Supports immune function, helps prevent allergies.
Lactobacillus fermentum Produces antioxidants and can help neutralise toxins. Reduces gastrointestinal inflammation.
Bifidobacterium animalis Specifically adapted to the gastrointestinal tract of animals. Enhances digestion, supports immune health.
Bifidobacterium bifidum Assists in breaking down complex carbohydrates. Promotes healthy digestion, helps in preventing infections.
Enterococcus faecium Often used in canine probiotics, supports gut balance. Improves stool quality, supports overall gut health.

(*) In a 2014 study, it was shown that Bacillus subtilis (the old name for what is now Bacillus Velezensis) "significantly increased Lactobacillus count in the caecum and ileal parts of the intestine, as well as the in the faeces". In addition, it also lowered E. Coli, Clostridium perfringens and Salmonella counts in the caecum, ileal regions, large intestines and in the faeces. (source)

Of all the ones above, Bacillus Velezensis is the only one that research shows to stimulate production of Lactobacillus. As you can see, Lactobacillus has a wide range of benefits in animals.

For this reason, we have opted to make our probiotics for dogs powder out of Bacillus Velezensis rather than other strains. We felt that it is better to administer a widely studied probiotic in dogs, that also directly stimulates the production of other probiotics rather than directly administering high amounts of other probiotics.

The effect when given this way can be multiplied as it acts both directly and also empowers the organism to create its own beneficial probiotics.


5 Key Benefits of Probiotics for Your Dog

Digestive Health Support

Most dog owners associated probiotics with an improvement in the digestive health of their dog. This may include preventing diarrhoea, constipation, regulating bloating, preventing cramps, decreasing stool odour or perhaps attempting to regulate consistency and timing.

Probiotics for dogs can help achieve all the above and more.

With regard to dog stool odour specifically, this can be of huge benefit to dog owners!

Recent research from 2020 showed how the use of Bacillus subtilis/ Velezensis in dogs significantly reduced the smell of poop without having any detrimental effects on the digestibility of nutrients. (source)

This 2019 study also showed an enhanced fat and carbohydrate digestibility and a reduction in gut ammonia in dogs who were given Bacillus subtilis/ Velezensis. (source)


Enhanced Immune Function

Improving this community of good bacteria in your dog's gut has been shown to boost their immune system and improve the local production of antibodies.

We know that 70% of a dog's immune system is in the gut, so optimising this environment can make your dog more resilient to infections and allergies.

diagram showing dog's anatomy, the gut and immune system text

One way the dog's immune system achieves this is through promotion of the proliferation of intestinal helper T (Th) cell precursors into local Treg cells via the signals received from the gut. At the same time, they decrease the proliferation of Th17 (pro-inflammatory) cells.

The Treg cells act as a regulator to prevent out of control local inflammation affecting the intestinal wall. 

This excessive intestinal inflammation is what can lead to gastrointestinal issues if not adequately regulated by the gut. (source)


Skin and Coat Health

Some studies indicate that probiotics might improve the condition of a dog's skin and coat by reducing allergic reactions and enhancing overall appearance.

The skin is the largest organ in the bodies of dogs (as is in humans). It acts as the first barrier against pathogens and as a result, it gets exposed to a large number of environmental factors.

Some of the most common conditions affecting a dog's skin are:

  • Skin irritation
  • Skin allergies
  • Flea infestations
  • Bacterial skin infestations

Although pharmacological therapies may be needed to manage most of these, there is now a further emphasis on the initial prevention.

A high number of studies have shown a direct connection between skin health and gut health in dogs. It is also known that gut problems can be manifested by various skin issues such as rashes, dryness or inflammation. (source)

Gut Dysbiosis

Atopic dermatitis for example is closely linked to a "dysbiosis" in the gut.

Dysbiosis simply refers to an imbalance between the good and the bad bacteria inside the gut. This often means that the bad bacteria have overtaken the good ones.

And how do we fix dysbiosis?

You've guessed it...

We fix it by helping the body create more and more good bacteria inside the gut, which can therefore outgrow the harmful biome.

The majority of studies have so far focused on Lactobacillus inside the gut and its role on prevention and treatment of dogs with atopic dermatitis.

Our own probiotics contains Bacillus Velezensis as this has the role to stimulate the body to produce more Lactobacillus, while at the same time decrease the amount of bad gut bacteria. This double action magnifies the impact of our chosen probiotic.

With adequate supplementation and a re-balancing of your dog's gut flora, you therefore have the potential to improve their skin and coat health. An added benefit is that of making them more comfortable at the same time, if you can prevent itching or recurrent infections.


Reducing Bad Breath and Dental Issues

Certain strains of probiotics can help control the growth of harmful bacteria in the mouth, leading to fresher breath and potentially less dental disease.

Although not extensively studied, it is postulated that certain strains of probiotics such as Lactobacillus acidophilusLactobacillus salivarius and Lactobacillus reuteri may help improve oral health in dogs.


Lactobacillus Acidophilus

A recent study from 2022 confirms that Lactobacillus acidophilus in particular was found in higher concentrations in dogs with good oral health. On the contrary, those with poor oral health had a low concentration of this particular probiotic. (source)


Lactobacillus Salivarius

The other potential candidate, Lactobacillus salivarius has also been studied in a couple of recent studies. It was shown to prevent oral growth of the bacteria responsible for causing gingivitis and periodontitis. (source)

Another study also showed it might decrease the amount of candida in the mouth. (source)

Lactobacillus Reuteri

Not as much information available about Lactobacillus Reuteri, but preliminary studies hypothesize that this might also have a role in improving oral health. (source)


Behaviour and Stress Reduction

The connection between gut health and behaviour or mood is referred to as the "gut-brain axis". This is a relatively new, but exciting area of research, in both dogs and humans.

The idea is that the gut and brain communicate with each other through various pathways, including neural, hormonal, and immune connections.

Probiotics work on directly altering the gut microbiome, therefore influencing these pathways and the signalling that goes towards the brain. This in turn dictates what hormones are released and what the neural signalling is to the rest of the body.

The research in this area is still emerging, but early research shows that Lactobacillus rhamnosus is one of the bacteria that may be involved.

Research from 2020 showed that dogs with more aggressive behaviour had a significantly lower level of Lactobacillus rhamnosus than those more approachable. (source)

This is an exciting area to watch for the future though - a couple of other studies looking at dogs are currently in progress.


How to Introduce Probiotics Into Your Dog's Diet

As long as you go for a probiotic widely studied in dogs, you are likely to get the benefits from this in a safe way.

The probiotic that's probably most widely studied in dogs and other animals is Bacillus subtilis C-3102)/ Bacillus Velezensis. We know that the side effects are minimal from this as long as the feeding guidelines are followed.

As this is the safest probiotic, it's also the one that the veterinarian team at Fetched prefers. For this reason, we opted to create our probiotic blend based on this, in combination with four other prebiotics and postbiotics.

After your dog has had a daily probiotic for 3-4 weeks, you should be able to notice some early changes. Of course, if you notice any adverse reactions, then consult with your vet immediately and follow their advice.

Consider Natural Probiotic Sources

Don't forget that probiotics for dogs are also naturally found in a variety of foods. Fermented foods like kefir or yogurt (without added sugars or artificial sweeteners) might also provide beneficial bacteria.



If you ask me, I think it's pretty cool that probiotics for dogs are so widely available and created in a safe way nowadays. The research is overall still in the early stages, but as we have seen, there are already significant benefits of probiotics in the strains so far studied in dogs.

Incorporating probiotics into your dog's diet may provide a multitude of health benefits that contribute to their overall wellbeing! You can make a start today in a safe and balanced way that has a high chance of improving your dog's wellbeing!



I have used a wide number of Pubmed references and scientific books in writing this article. Here are all of them, in case you would like to read more in depth on this topic.

Jeong JS, Kim IH. Effect of Bacillus subtilis C-3102 spores as a probiotic feed supplement on growth performance, noxious gas emission, and intestinal microflora in broilers. Poult Sci. 2014 Dec;93(12):3097-103.

Schauf, S., Nakamura, N., & Castrillo, C. (2019). Effect of Calsporin® (Bacillus subtilis C-3102) addition to the diet on faecal quality and nutrient digestibility in healthy adult dogs. Journal of Applied Animal Nutrition, 7, E3.

Bastos, T.S., de Lima, D.C., Souza, C.M.M. et al. Bacillus subtilis and Bacillus licheniformis reduce faecal protein catabolites concentration and odour in dogs. BMC Vet Res 16, 116 (2020).

Ian R. Tizard, Sydney W. Jones. The Microbiota Regulates Immunity and Immunologic Diseases in Dogs and Cats, Veterinary Clinics of North America: Small Animal Practice, Volume 48, Issue 2, 2018.

Craig JM. Atopic dermatitis and the intestinal microbiota in humans and dogs. Vet Med Sci. 2016 Feb 23;2(2):95-105.

Maguire M, Maguire G. The role of microbiota, and probiotics and prebiotics in skin health. Arch Dermatol Res. 2017 Aug;309(6):411-421.

Caramia G, Atzei A, Fanos V. Probiotics and the skin. Clin Dermatol. 2008 Jan-Feb;26(1):4-11.

You I, Mahiddine FY, Park H, Kim MJ. Lactobacillus acidophilus novel strain, MJCD175, as a potential probiotic for oral health in dogs. Front Vet Sci. 2022 Sep 2;9:946890.

Scariya, L., Nagarathna, D.V. and Varghese, M. (2015) Probiotics in Periodontal Therapy. International Journal of Pharma and Bio Sciences, 6, 242-250.

Burton, J.P., Drummond, B.K., Chilcott, C.N., Tagg, J.R., Thomson, W.M., Hale, J.D.F. and Wescombe, P.A. (2013) Influence of the Probiotic Streptococcus salivarius Strain M18 on Indices of Dental Health in Children: A Randomized Double-Blind, Placebo-Controlled Trial. Journal of Medical Microbiology, 62, 875-884.

Hatakka K, Ahola AJ, Yli-Knuuttila H, et al. Probiotics Reduce the Prevalence of Oral Candida in the Elderly—a Randomized Controlled Trial. Journal of Dental Research. 2007;86(2):125-130.

Yang KM, Kim JS, Kim HS, Kim YY, Oh JK, Jung HW, Park DS, Bae KH. Lactobacillus reuteri AN417 cell-free culture supernatant as a novel antibacterial agent targeting oral pathogenic bacteria. Sci Rep. 2021 Jan 15;11(1):1631.

Mondo E, Barone M, Soverini M, D'Amico F, Cocchi M, Petrulli C, Mattioli M, Marliani G, Candela M, Accorsi PA. Gut microbiome structure and adrenocortical activity in dogs with aggressive and phobic behavioral disorders. Heliyon. 2020 Jan 29;6(1):e03311.

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