WHY DOES MY DOG EAT GRASS?

“Why does my dog eat grass?”

It is one of those questions we hear regularly in veterinary practice. While occasional grass eating is usually nothing to worry about, frequent or obsessive grass eating can sometimes give us useful clues about what is happening with your dog’s diet, digestive system, gut microbiome, or even their emotional wellbeing.

Is grass eating normal?

For many dogs, yes. Dogs are naturally opportunistic eaters, and eating plant material is not necessarily abnormal. Some dogs simply enjoy the texture, taste or activity of grazing, particularly when they are outside and have access to fresh grass.

Research also suggests that grass eating is not simply a sign that a dog is trying to make themselves vomit. In fact, most dogs that eat grass do not vomit afterwards. So if your dog occasionally munches on a few blades of grass and is otherwise bright, happy, eating normally and passing normal stools, there may be no problem to fix at all.

However, frequency and context matter. A dog that suddenly starts frantically eating large amounts of grass, particularly alongside lip licking, swallowing, drooling, vomiting, diarrhoea, abdominal discomfort or changes in appetite, deserves closer attention.

Could your dog's diet be contributing?

This is where we can look a little deeper. Grass provides fibre and plant matter, and some dogs may instinctively seek out roughage when their diet is relatively low in fibre or when their gastrointestinal tract isn't functioning optimally.

This doesn't necessarily mean your dog is “missing a vitamin” or that their food is nutritionally deficient. In fact, adding lots of supplements simply because a dog eats grass isn't usually the answer.

Instead, we look at the whole diet. Is your dog eating an appropriate amount for their life stage and activity level? Is the diet nutritionally complete and balanced? Does it contain an appropriate amount and variety of fibre? Is it highly processed? Is your dog eating only one type of food or are there safe opportunities for dietary variety?

For some dogs, introducing appropriate sources of soluble and insoluble fibre can help support normal gastrointestinal function and stool quality. Depending on the individual patient, this may include carefully selected vegetables, suitable fibre sources or supplements such as psyllium, pumpkin or other veterinary recommended prebiotic fibres.

More fibre isn't automatically better, however. Too much, or the wrong type of fibre, can contribute to gas, bloating or loose stools.

What about the gut microbiome?

The gastrointestinal tract is home to an enormous community of bacteria and other microorganisms collectively known as the gut microbiome. These organisms play important roles in digestion, immune function and intestinal health.

If your dog has a history of recurrent diarrhoea, constipation, dietary indiscretion, antibiotic use, food sensitivities or other digestive problems, we may consider whether their gut health needs some additional support.

This is where prebiotics and probiotics may have a role. Prebiotics provide nourishment for beneficial gut bacteria, while probiotics provide specific live microorganisms. Some dogs may benefit from targeted probiotic support, particularly when there is an identifiable gastrointestinal issue, although not every healthy dog needs a daily probiotic.

Gentle digestive herbs may also have a place in an integrative approach, but herbs should be selected according to the individual animal rather than simply given because they are “natural”.

Could they simply need more enrichment?

Absolutely! Sometimes the answer has nothing to do with nutrition.

Dogs explore the world with their mouths and noses. Grass is interesting, it smells, moves, has different textures and provides an opportunity to forage.

If your dog tends to eat grass when they are bored, under stimulated or simply enjoying being outside, increasing mental enrichment and natural foraging opportunities may help.

Try scatter feeding part of their meal through the garden, using a snuffle mat, offering safe chew items, providing lick mats or creating simple scent games.

Foraging is a natural behaviour, and allowing dogs to use their noses and work for some of their food can be incredibly enriching.

Should I stop my dog eating grass?

Not necessarily, but where they are eating it matters.

Grass can potentially expose dogs to herbicides, pesticides, fertilisers, snail bait and other garden chemicals. Dogs may also ingest parasites or faecal contamination from other animals.

If your dog enjoys grazing, provide access to clean, untreated grass and avoid areas that may have been chemically treated.

It is also worth remembering that some plants are toxic to dogs, so grazing should never mean allowing unrestricted access to unknown vegetation.

What can I do at home?

Rather than immediately trying to suppress the behaviour, take a step back and ask why is my dog doing this?

Look at the bigger picture:

Diet: Is your dog's food nutritionally complete and appropriate for them? Could their diet benefit from greater fibre or variety?

Digestion: Are there other signs such as gas, gurgling, constipation, diarrhoea, mucus in the stool, frequent vomiting or changes in appetite?

Gut support: Depending on the individual patient, probiotics, prebiotics or specific fibre supplements may be useful.

Enrichment: Are they getting enough sniffing, chewing, licking, exploring and foraging opportunities?

Lifestyle: Is grass eating happening mainly when they are bored, anxious or excited?

Medical causes: Has the behaviour suddenly changed or become excessive?

This holistic approach is often much more useful than simply telling a dog “no” every time they eat grass.

When should I be concerned?

Occasional grazing in an otherwise healthy dog is generally not alarming.

However, persistent or sudden excessive grass eating should prompt a veterinary assessment, particularly if it is accompanied by vomiting, diarrhoea, poor appetite, weight loss, lethargy, excessive thirst, abdominal pain, repeated swallowing or lip licking, or changes in bowel habits.

Grass eating can occasionally occur alongside gastrointestinal disease, dietary intolerance, parasites or other medical problems, so we don't want to assume that every dog simply needs a supplement.

Grass eating isn't automatically a problem, and it isn't automatically a sign that your dog has an upset stomach.

Sometimes it is simply normal canine behaviour. Sometimes it reflects a desire for fibre or plant material. Sometimes it is related to gut health, diet or digestive discomfort. And sometimes, quite simply, your dog just likes eating grass!

Rather than treating the behaviour in isolation, an integrative approach looks at the whole dog, their diet, digestion, microbiome, lifestyle, enrichment and overall health.

If your dog's grass eating has suddenly increased, is becoming obsessive, or is accompanied by other digestive symptoms, it's worth investigating the underlying cause rather than simply trying to stop the behaviour.