Why is my dog gassy? Causes, digestion, and better diet choices

Every dog passes gas. It's a normal part of digestion and nothing to worry about on its own. But if your dog is clearing the room on a regular basis, or the smell has noticeably changed, something in their diet or digestive system probably isn't working as well as it should.

Excessive gas in dogs is usually fixable, and the answer often starts with what's going into the bowl.

What causes gas in dogs?

Gas builds up in your dog's digestive system in two ways: they either swallow air while eating, or bacteria in their gut produce gas as they break down food. Most of the time, it's a combination of both.

Diet is the most common trigger. When food isn't broken down properly in the small intestine, it passes into the large intestine, where gut bacteria ferment it. That fermentation produces gas. The more undigested material that reaches the large intestine, the more gas your dog produces. Sulphur-containing compounds in certain ingredients are what create the particularly foul-smelling variety. If the food you're feeding doesn't suit your individual dog's digestion, gas is often one of the first signs.

Sudden diet changes are another frequent cause. Switching food without a gradual transition can overwhelm the digestive system and lead to a temporary spike in gas, loose stools, or both.

Table scraps and human food are common culprits, particularly fatty foods, dairy, and anything containing onion, garlic, or heavy seasoning. These are hard for dogs to process and often lead to digestive upset.

Swallowing air (sometimes called aerophagia) happens when dogs eat too quickly, eat immediately after exercise, or compete with other pets at mealtimes. Flat-faced breeds like French Bulldogs, Pugs, and Bulldogs are particularly prone to this because of their shortened airways. They tend to gulp more air with every mouthful, which is why these breeds are often among the gassiest.

Food sensitivities and intolerances are a less obvious but genuinely common cause. If your dog has a persistent gas problem that doesn't improve with basic dietary changes, an underlying sensitivity to a specific ingredient could be the reason.

How your dog's gut health affects gas

Around 70% of a dog's immune system is connected to the gut, and the balance of bacteria living there plays a bigger role in digestion than most pet parents realise.

A healthy gut microbiome breaks food down efficiently, absorbing nutrients in the small intestine before material moves on. When that balance is disrupted, the digestive process becomes less efficient. More partially digested food reaches the large intestine, where it ferments and produces excess gas.

This can be triggered by a course of antibiotics, a prolonged period of stress, a sudden change in diet, or simply by feeding a food that doesn't agree with your dog's system over time.

Prebiotics play a key role here. They're a type of plant fibre that feeds the beneficial bacteria already living in your dog's gut, helping them to outcompete the less helpful strains. A diet that includes prebiotics as part of its formulation may help support a balanced microbiome.

Could it be a food sensitivity?

If your dog's gas is persistent and doesn't respond to the usual fixes (slower eating, gradual food changes, cutting out table scraps), a food sensitivity is worth investigating.

A food sensitivity isn't the same as a true allergy. Allergies involve the immune system and tend to produce skin reactions, itching, and ear infections alongside digestive symptoms. Sensitivities are more of a digestive intolerance, where the gut simply struggles to process a particular ingredient. The result is often chronic gas, soft stools, or intermittent stomach upset.

Some dogs may react to certain proteins, grains, or additives, though sensitivities vary between individuals. The challenge is working out which ingredient your dog is reacting to, especially if their current food contains several potential triggers at once.

This is where single-source protein recipes can be useful. By feeding a diet built around one named animal protein, you simplify what the digestive system has to process. If the gas improves, you know the trigger was likely one of the ingredients you've removed. If it doesn't, you can try a different protein and continue narrowing it down.

An elimination diet supervised by your vet is the most reliable way to identify a specific trigger, but switching to a single-source protein food is a practical first step that many pet parents find helpful.

How diet can influence your dog's digestion

If the food you're feeding doesn't suit your dog's individual digestive system, excess gas is a common result. Some dogs digest certain ingredients more easily than others, and finding the right match for your dog can take some trial and adjustment.

A diet built around a clearly named, single-source animal protein can make it easier to monitor how your dog responds to what they're eating. Grain-free recipes may suit dogs who show signs of sensitivity to specific grains, though dogs who tolerate grains well don't need to avoid them.

The difference when you find the right food for your dog is often visible within a couple of weeks: firmer stools, less gas, and a dog that seems more comfortable after meals.

How AATU recipes support healthy digestion

Our recipes are crafted with digestion in mind. Every AATU dry dog food recipe is built around 80% single-source, freshly prepared meat or fish ingredients and 20% of our Superfood Blend™ of fruits, vegetables, herbs, spices, and botanicals. There are no grains, no fillers, and nothing artificial.

We cook every batch using our unique Low and Slow™ method to lock in nutrients, and every recipe includes added prebiotics to support a balanced gut microbiome. With 2.5kg of raw ingredients in every 1kg of food, the nutritional density means your dog gets more from every meal.

For dogs who do well with variety, or who benefit from the added moisture and palatability of wet food, our 90/10 wet dog food recipes work well alongside dry as a topper or a complete meal on their own. Both formats are single-source protein and grain-free, making them well-suited to dogs with sensitive digestion.

How to reduce your dog's gas

Most cases of excessive gas can be improved with a few practical changes.

Transition to the new food gradually. If you're switching your dog's diet, do it over seven to 10 days, starting with a small proportion of the new food mixed in with the old and increasing it slowly. This gives the gut bacteria time to adjust.

Feed smaller meals more frequently. Two smaller meals rather than one large one reduces the volume of food the digestive system has to process at once.

Slow down fast eaters. Slow-feeder bowls, puzzle feeders, and lick mats all help reduce the amount of air your dog swallows at mealtimes. This is especially important for flat-faced breeds.

Cut out table scraps. Human food is one of the most common causes of digestive upset in dogs, and even small amounts of fatty, seasoned, or dairy-based food can trigger gas.

Keep up with regular worming. Intestinal parasites can disrupt digestion and contribute to gas. Stick to your vet's recommended worming schedule.

Maintain regular exercise. Light, gentle movement after meals can help support digestion, but avoid vigorous exercise immediately after feeding. Dogs that are sedentary after meals tend to be gassier.

When to see your vet

Occasional gas is normal. But if your dog's flatulence is persistent, worsening, or accompanied by other symptoms, it's time for a vet visit.

Contact your vet if gas accompanies vomiting, diarrhoea, weight loss, lethargy, loss of appetite, blood in stools, or a bloated or painful abdomen.

Underlying conditions that can cause chronic gas include inflammatory bowel disease, pancreatitis, intestinal parasites, small intestinal bacterial overgrowth (SIBO or ARE), and in rare cases, intestinal cancer. Your vet may recommend stool samples, blood tests, or imaging to rule these out.

Persistent, unexplained gas always warrants investigation. Most of the time, the answer is dietary, but it's better to rule out anything more serious early.

FAQs

Is it normal for dogs to fart a lot?

Some gas is completely normal. But if your dog is consistently gassy, or the smell has changed noticeably, it usually points to something in their diet that isn't being digested well. Reviewing what you're feeding and how your dog responds to it is a good starting point.

What food is best for a gassy dog?

A food with a clearly named, single-source animal protein and added prebiotics to support gut health may help. Single-source recipes make it easier to identify if a specific ingredient is causing the issue.

Can dog food cause gas?

Yes. If the food you're feeding doesn't suit your individual dog's digestion, gas is often one of the first signs. Every dog responds differently to different ingredients, so finding the right match for your dog may take some adjustment.

Do probiotics help with dog gas?

They can, particularly if your dog's gut microbiome is out of balance. Prebiotics (which feed the beneficial bacteria already in the gut) are equally important and may be best delivered as part of the overall diet rather than as a standalone supplement.

Why does my dog's gas smell so bad?

Foul-smelling gas is usually caused by sulphur-producing bacteria breaking down poorly digested food in the large intestine. Certain ingredients are more likely to produce strong-smelling gas than others. If the smell has changed or worsened, reviewing your dog's diet is a good first step.

Can grain-free food reduce dog gas?

For some dogs, yes. Some dogs may find certain grains harder to digest, which can contribute to fermentation in the gut. However, dogs who tolerate grains well don't need to avoid them. The most important thing is finding a diet that suits your individual dog's digestion.

How long does it take for a diet change to reduce gas?

Most dogs show noticeable improvement within two to four weeks of switching to a food that better suits their digestion, provided the transition is done gradually over seven to 10 days. If gas persists beyond a month on a new diet, speak to your vet about possible underlying causes.

Are certain dog breeds more gassy than others?

Flat-faced breeds like French Bulldogs, Pugs, Bulldogs, and Shih Tzus tend to be gassier because they swallow more air when they eat due to their shortened airways. Larger, deep-chested breeds like Boxers and German Shepherds can also be prone to bloat or gas. For these breeds, slow-feeder bowls and finding a diet that suits their digestion are particularly helpful.