The Gut-Brain Connection in Dogs & Cats: How Gut Health, Probiotics & Nutrition Influence Behaviour
Have you ever noticed your dog becoming anxious after digestive upset? Or your cat seeming irritable, withdrawn, or stressed for no obvious reason?
While behaviour is influenced by genetics, training and training methods, environment, and health, emerging research is revealing another important player—the gut.
Known as the gut-brain axis, this remarkable communication system links the digestive tract with the brain. A healthy gut doesn't just improve digestion—it can influence mood, stress resilience, learning, and behaviour in both dogs and cats.
What is the Gut-Brain Connection?
The gut and brain are in constant communication through:
• The vagus nerve (the body's information superhighway)
• Hormones
• The immune system
• Neurotransmitters produced by gut bacteria
Approximately 90% of the body's serotonin is produced in the digestive tract. While this serotonin doesn't directly enter the brain, it plays an important role in gut function and communicates with the nervous system through the gut-brain axis, influencing overall health and wellbeing.
When the gut microbiome becomes imbalanced (known as dysbiosis), these communication pathways can be disrupted, potentially contributing to:
• Anxiety and nervousness
• Hyperactivity
• Poor focus
• Increased stress responses
• Fearful behaviour
• Changes in appetite
• Digestive discomfort
Why Gut Health Matters for Behaviour
The gut contains trillions of beneficial bacteria that help regulate:
• Digestion
• Immune health
• Inflammation
• Nutrient absorption
• Neurotransmitter production
When these beneficial bacteria are thriving, pets often experience better overall health, and many guardians notice improvements in mood, resilience and behaviour.
Conversely, poor-quality diets, antibiotics, chemical flea & tick preventatives, pharma drugs, stress, illness, environmental toxins and highly processed foods can reduce microbial diversity and upset this delicate balance.
Signs Your Pet's Gut May Need Support
While every pet is unique, signs of gut imbalance may include:
• Frequent diarrhoea or constipation
• Gas or bloating
• Food sensitivities
• Excessive licking or chewing
• Skin problems
• Recurring ear infections
• Anxiety or nervousness
• Restlessness
• Poor recovery from stressful situations
Behavioural changes should always be discussed with your veterinarian, particularly if they occur suddenly or are severe.
The Role of Probiotics
Probiotics are beneficial live microorganisms that help restore a healthy balance within the gut microbiome.
Research into "psychobiotics"—specific probiotic strains that may influence behaviour—is growing rapidly in both human and veterinary medicine.
Potential benefits include:
• Supporting a balanced stress response
• Improving digestive health
• Supporting immune function
• Helping reduce inflammation
• Promoting a healthier gut microbiome
• Supporting emotional wellbeing
Not all probiotics are created equal. Different strains perform different functions, so it's important to choose products specifically formulated for dogs and cats.
Food Really Does Affect Mood
Nutrition provides the building blocks for both physical and mental health—and the health of your pet's gut microbiome.
One of the best ways to support a healthy gut is by feeding a diverse range of fresh, whole foods. Just as diversity is important in nature, a varied diet helps nourish a wider range of beneficial gut bacteria. A more diverse microbiome is associated with better digestive health, immune function and overall wellbeing.
Rather than relying solely on highly processed foods, aim to include a variety of fresh, species-appropriate ingredients over time, such as quality animal proteins, colourful vegetables, healthy fats and functional foods. Variety doesn't have to happen in every meal—the goal is to provide diversity across weeks and months.
Omega-3 Fatty Acids
Support healthy brain function while helping regulate inflammation throughout the body.
Prebiotic Fibre
Ingredients such as pumpkin, chicory root, inulin and other natural fibres help feed beneficial gut bacteria.
Fermented Foods
Where appropriate and introduced gradually, fermented foods may help support microbial diversity. Always choose pet-safe options.
Polyphenol-Rich Foods
Blueberries, leafy greens and colourful vegetables contain antioxidants that help support both gut health and the microbiome.
Bone Broth
A high-quality bone broth is a nourishing addition to your pet's diet. Naturally rich in amino acids such as glycine and glutamine, along with collagen and minerals, bone broth helps support hydration, digestive health and overall wellbeing. It can also be an excellent way to encourage fussy eaters or pets recovering from illness to eat and drink more readily.
Highly Digestible Protein
Quality animal protein supplies essential amino acids required for neurotransmitter production and supports healthy muscle maintenance.
Managing Stress Naturally
Nutrition is only one part of supporting emotional wellbeing.
Helping your pet feel calm and confident also involves:
• Consistent daily routines
• Avoiding long periods of confinement
• Regular exercise
• Mental enrichment
• Positive reinforcement training
• Quality sleep
• Environmental enrichment
• Addressing pain or underlying illness
When combined with targeted gut support and a nutritious diet, these strategies can make a significant difference to your pet's overall wellbeing.
Supporting Your Pet Starts in the Gut
If your dog or cat experiences digestive issues, food sensitivities, anxiety or behavioural changes, supporting their gut health can be one of the most valuable steps you can take.
A healthy gut microbiome supports far more than digestion—it also plays an important role in immune health, emotional wellbeing and overall vitality. While probiotics are not a cure for behavioural disorders, they can be an effective part of a holistic wellness plan alongside appropriate nutrition, veterinary care and behaviour modification.
At Aussie Pooch, we've carefully curated an evidence-backed Gut Health Collection to help nourish the digestive system and restore microbial balance naturally.
If you're not sure where to begin, the Digestive Reset is the perfect starting point. Designed to gently support the digestive system, replenish beneficial bacteria and promote a healthy gut microbiome, it's one of our most popular solutions for pets needing a fresh start.
👉 Explore our Gut Health Collection
👉 Discover Digestive Reset
Helping your pet feel better from the inside out may be the key to a happier, healthier and more balanced life.
As always, if your pet has ongoing digestive issues or sudden behavioural changes, consult an integrative or holistic veterinarian to rule out any underlying medical conditions before introducing new supplements or making significant dietary changes.
References
Sacoor, C., et al. (2024). Gut-Brain Axis Impact on Canine Anxiety Disorders. Veterinary Medicine International. This comprehensive review summarises current evidence that the gut microbiome communicates with the brain through neural, endocrine, immune and metabolic pathways, and discusses the potential role of probiotics and nutrition in supporting dogs with anxiety-related behaviours.
Kiełbik, P., et al. (2024). The Relationship between Canine Behavioral Disorders and Gut Microbiota. Animals, 14(14), 2048. This review examines the links between gut dysbiosis, inflammation, neurotransmitter production and behavioural disorders in dogs, while highlighting the need for further clinical research.
Homer, B., et al. (2023). Gut Microbiota and Behavioural Issues in Production, Performance and Companion Animals. Animals. This review explores how changes in the gut microbiome may influence mood, stress responses and behaviour across animal species, including companion animals.
Pellowe, S. D., et al. (2025). Gut Microbiota Composition Is Related to Anxiety and Aggression in Pet Dogs. Scientific Reports. This study found that gut microbiota profiles could predict behavioural groupings in pet dogs and identified bacterial genera associated with anxiety, providing further support for the gut-behaviour connection.
