Grass-eating is one of the most common dog behaviours Australian dog owners ask about. The short answer is: it is usually normal. The more useful answer covers the four distinct reasons dogs eat grass, how to tell the difference between casual grazing and grass-eating driven by gut discomfort, when to see a veterinarian, what the peer-reviewed research actually found (it contradicts most of what you read online), and what the dietary drivers look like when diet is the cause.
What the research actually says
A large-scale study of 1,571 dog owners found that 68% of dogs eat plants daily or weekly, with grass the most common. Only 8% showed illness before eating. Only 22% vomited afterward. The lead researchers concluded that grass-eating is a normal behaviour in dogs, unrelated to illness in the majority of cases, reflecting an innate predisposition inherited from wild canid ancestors. The popular belief that dogs eat grass to make themselves vomit is not supported by the evidence.
What Rogue Raw customers say about grass-eating and diet
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"My border collie had been eating grass every morning for two years. Added raw green tripe once weekly and the urgency-driven morning grass-eating stopped within a month. She still has the occasional nibble on walks but the compulsive behaviour is gone."
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"My staffy was eating grass and vomiting bile regularly. Vet ruled out medical causes. Switched to Rogue Raw venison with weekly green tripe and sardines twice weekly. The bile vomiting stopped after three weeks and the grass-eating dropped significantly."
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"Never thought grass-eating had a dietary connection until my golden's obsessive morning grazing reduced dramatically after adding green tripe jerky daily and moving to a proper raw rotation. Two years in and she barely touches the grass now."
The four reasons dogs eat grass: what research actually supports
Reason 1: Ancestral instinct and parasite purging
The most strongly supported explanation for grass-eating in dogs is ancestral instinct. Wild canids including wolves, coyotes, jackals, and foxes all eat plant material as a normal part of their behaviour. Studies of wolf and coyote scat show plant material in 11 to 47% of samples, with grass being the most common plant. Dogs are domestic carnivores that retain the behavioural repertoire of their wild canid ancestors, and grass-eating appears to be part of that repertoire.
A 2008 study by Sueda, Cliff, and Hart proposed a specific mechanism: in wild canids, eating grass may have served as a natural intestinal nematode-purging behaviour. Leaf and grass material passing through the intestinal tract increases gut motility and can physically wrap around and expel intestinal worms, similar to the behaviour observed in wild chimpanzees. Modern dogs with regular parasite prevention have reduced need for this mechanism, but the instinct appears to persist regardless.
Younger dogs eat grass more frequently than older dogs in all survey studies, consistent with an instinct that diminishes with age as immune system maturity increases and the practical need for parasite purging reduces.
Reason 2: Gut discomfort, nausea, or reflux
Some dogs eat grass urgently and compulsively when experiencing gut discomfort. This is the subset of grass-eating that is most likely to be medically or dietarily relevant. The key distinction from casual grazing is urgency: a dog that wakes up and immediately seeks out grass to eat rapidly and frantically is showing a different behaviour from a dog that takes a casual nibble while sniffing on a walk.
Specific gut conditions associated with grass-seeking behaviour include gastric acid reflux (bilious vomiting syndrome, where dogs vomit bile on an empty stomach, typically in the early morning), inflammatory bowel disease, gut dysbiosis, and general nausea from any cause. If your dog consistently seeks grass first thing in the morning before eating, bilious vomiting syndrome is a likely explanation. This responds well to a small late-evening meal to buffer stomach acid overnight.
Reason 3: Fibre or digestive roughage seeking
Grass contains fibre. Dogs fed very low-fibre diets may seek grass as a dietary supplement. The evidence here is more mixed than is often claimed: the large survey study found no significant difference in grass-eating rates between dogs on raw food, table scraps, or commercial balanced diets. However, a documented case of a Miniature Poodle whose daily grass-eating of over five years resolved completely when placed on a high-fibre commercial diet suggests that fibre deficiency can be a driver in at least some dogs.
For raw-fed dogs, the fibre consideration is relevant when running an 80:10:10 prey model raw diet without any plant matter. The addition of appropriate vegetable matter, green tripe (which provides prebiotic fibre from partially fermented rumen content), or occasional small amounts of fibrous vegetables can reduce grass-seeking in raw-fed dogs showing this pattern.
Reason 4: Boredom, exploration, and learnt behaviour
Dogs, particularly puppies and young dogs, explore their environment with their mouths. Grass is always present, has a texture and taste that some dogs find appealing (particularly fresh spring growth), and is easily accessible. Some dogs simply enjoy chewing grass for sensory reasons with no underlying medical or nutritional driver.
Boredom-driven grass-eating typically increases when owner contact time decreases, during periods of less physical and mental stimulation, and in dogs who are otherwise well but left alone for long periods. It is not a nutritional problem. Increasing enrichment, interactive feeding, and mental stimulation typically reduces this behaviour without dietary intervention.
How to tell the difference: normal grazing vs concerning grass-eating
| Normal grazing | Potentially concerning |
|---|---|
| Occasional, relaxed nibbling | Urgent, frantic, compulsive grass-seeking |
| No signs of distress before or after | Licking lips, gulping, drooling, restlessness before eating grass |
| Normal stool quality maintained | Vomiting after, loose stools, or bile vomiting |
| Normal appetite and energy maintained | Reduced appetite, weight loss, or lethargy |
| Happens occasionally or seasonally | Happens daily, especially first thing in the morning |
| Dog otherwise bright and well | Alongside swollen abdomen, bloating, or signs of pain |
If your dog shows any concerning signs from the right column, book a veterinary assessment. Grass-eating is a clue, not a diagnosis. Medical causes including gastric reflux, IBD, and pancreatitis need to be ruled out before attributing grass-eating solely to diet.
When to see a vet about your dog eating grass
Seek veterinary attention promptly if your dog is eating large amounts of grass with urgency and then vomiting repeatedly, if the vomit contains blood, if the grass-eating is accompanied by a swollen or distended abdomen (which could indicate bloat), if your dog appears weak or in pain, or if the grass-eating is a new sudden behaviour change in an otherwise settled dog.
Book a routine veterinary appointment (not urgent) if the grass-eating is daily and accompanied by loose stools or soft stools, if there is a pattern of early-morning grass-eating followed by bile vomiting, or if your dog has lost weight alongside the grass-eating behaviour. These presentations benefit from physical examination and possibly bloodwork to rule out metabolic causes before dietary intervention.
The risks of grass-eating in Australian conditions
Grass itself is not toxic to dogs. The risks in the Australian environment come from what may be on or around the grass.
Pesticides and herbicides: Lawns, parks, council verges, and golf course surrounds in Australia are routinely treated with herbicides (glyphosate, 2,4-D), insecticides, and synthetic fertilisers. Grass ingested shortly after treatment can cause significant toxicity. Signs include drooling, vomiting, tremors, and lethargy. If you suspect your dog has eaten treated grass, contact your veterinarian immediately.
Intestinal parasites: In Australia, grass in public areas can be contaminated with faecal residue from other dogs and animals carrying hookworm, roundworm, whipworm, and giardia eggs. Grass-eating dogs who are regularly dewormed and on monthly heartworm prevention have lower parasite risk, but routine faecal testing is appropriate for consistent grass-grazers.
Grass seeds: Australian grass varieties (particularly during summer and early autumn) produce seeds that can penetrate skin, ear canals, and paw tissue, causing painful abscesses. Long grass and seeding grass carry higher risk than short lawn grass. Check ears, paws, and body folds after walks in seeding grass.
How raw feeding and diet address the dietary causes of grass-eating
When grass-eating has a dietary driver, the solution is in the diet. The five Rogue Raw products below address the three dietary mechanisms most likely to drive grass-seeking behaviour: gut dysbiosis and digestive discomfort, inadequate dietary fibre or nutrient variety, and the systemic inflammation from omega-6 excess that can produce the gut irritability underpinning grass-seeking in sensitive dogs.
Green tripe: the most direct dietary intervention for gut-driven grass-eating
Raw green tripe provides live Lactobacillus acidophilus, natural digestive enzymes (protease, lipase, amylase), and prebiotic fibre from partially fermented rumen content. For dogs whose grass-eating is driven by gut dysbiosis, insufficient digestive enzyme production, or the bile acid dysregulation that causes bilious vomiting, green tripe addresses the mechanism directly. The improvement Karen describes above (compulsive morning grass-eating resolving within a month of weekly green tripe) is consistent with the gut microbiome restoration timeline at which Lactobacillus colonisation becomes measurable. See our gut health guide for the full green tripe mechanism.
Protein digestibility and gut residue
Dogs on low-digestibility diets produce more fermentable residue in the colon, which alters gut microbiome composition and can produce excess gas, gut inflammation, and the vague digestive discomfort that sometimes drives grass-seeking. Raw food protein digestibility of 99.3% versus 79.5% for extruded kibble means significantly less undigested protein residue reaching the colon. For dogs showing grass-eating alongside loose stools, excess gas, or general digestive irregularity, improving protein digestibility through switching to a high-quality raw diet addresses the colonic fermentation that may be driving the behaviour. See our protein quality guide.
Omega-3 and gut inflammation
The omega-6 to omega-3 imbalance common in kibble-fed and some raw-fed dogs (particularly those eating primarily chicken without regular oily fish rotation) can produce chronic low-grade gut inflammation that manifests as intermittent digestive discomfort, loose stools, and the associated grass-seeking. EPA and DHA from sardines and salmon reduce this gut inflammatory environment through the same mechanism that reduces skin inflammation in atopic dogs. For raw-fed dogs showing persistent digestive sensitivity alongside grass-eating, adding sardines two to three times weekly often produces noticeable improvement in digestive stability within four to eight weeks. See our skin and gut guide.
The five Rogue Raw products that address dietary grass-eating
Every product below has been verified live on rogueraw.com.au before inclusion. Every Add to Cart button links directly to the exact product page. Every product name, image, and button points to the same URL.
Practical steps if your dog is eating grass frequently
Step 1: Assess the pattern
Is the grass-eating urgent and compulsive (gut discomfort likely) or casual and exploratory (instinct or boredom likely)? Is it happening mainly first thing in the morning before meals (bilious vomiting syndrome likely)? Is it accompanied by any other symptoms? Is it a new behaviour or long-standing? The pattern determines the appropriate response.
Step 2: Rule out medical causes
If the pattern suggests gut distress (urgency, pre-eating restlessness, frequent vomiting, loose stools), rule out medical causes with your veterinarian before attributing it to diet. Gastric reflux, IBD, pancreatitis, and giardia can all produce grass-seeking behaviour and need diagnostic confirmation before dietary management.
Step 3: Address dietary factors if diet is the driver
If medical causes are ruled out and the behaviour is dietary in origin, the priority interventions are: add weekly green tripe for gut microbiome restoration and digestive enzyme support, add sardines twice weekly for anti-inflammatory EPA and DHA, review protein digestibility and switch to a higher-quality protein source if currently on kibble or low-quality raw mince, and ensure adequate dietary fibre if on a strict 80:10:10 prey model raw diet without any plant matter. Use the Rogue Raw feeding calculator to confirm your dog's daily food amounts are appropriate for their weight and activity level.
Step 4: Address enrichment if boredom is the driver
If grass-eating is behavioural and not accompanied by any gut symptoms, increasing mental and physical stimulation typically reduces or eliminates the behaviour. Puzzle feeders, interactive food toys, additional daily exercise, and training sessions address the boredom and attention-seeking drivers. Green tripe jerky used as a training treat provides both the enrichment engagement and the gut microbiome support simultaneously. See the Rogue Raw feeding guide for interactive feeding ideas.
Why choose Rogue Raw
How Rogue Raw addresses the dietary causes of grass-eating
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Green tripe: the gut microbiome reset
Cold-washed raw green tripe provides live Lactobacillus acidophilus, digestive enzymes, and prebiotic fibre in the form most appropriate to a carnivore's gut. The direct address to the gut dysbiosis driving most compulsive grass-eating behaviour.
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99.3% protein digestibility
Less undigested colonic residue means less fermentative gut dysbiosis, less gas, and less of the vague digestive discomfort that drives grass-seeking in many dogs on lower-digestibility food.
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Whole-food omega-3 anti-inflammatory support
EPA and DHA from sardines and salmon reduce the gut inflammatory environment associated with chronic digestive sensitivity. Addresses the omega-6/omega-3 imbalance underlying gut irritability in sensitive dogs.
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No sulphite preservatives
Human-grade supply chain throughout. Sulphite preservatives in pet-grade meat disrupt B vitamin metabolism and can contribute to gut irritation. Eliminated at source.
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30,000+ Australian dogs fed
The improvements Karen, Pete, and Leanne describe above are consistent with what we see across our customer base when gut-driven grass-eating is addressed through diet rather than suppressed through behaviour management alone.
Related reading
Best food for dogs gut health - the complete gut microbiome guide and how green tripe addresses digestive dysbiosis
Raw food for dog skin and coat - how omega-3 anti-inflammatory support addresses gut and skin inflammation simultaneously
Why chicken causes allergies in dogs - protein selection for dogs where grass-eating accompanies food sensitivity signs
Why raw feeding is the best diet for your dog - the full biological case for addressing digestive health through species-appropriate nutrition
Frequently asked questions: why do dogs eat grass?
Why do dogs eat grass?
Four reasons supported by research: (1) ancestral instinct from wild canid ancestors who routinely consumed plant material; (2) gut discomfort from nausea, reflux, or dysbiosis driving grass-seeking; (3) fibre or roughage seeking in low-fibre diets; (4) boredom, exploration, or learnt behaviour. The large-scale research found 68% of dogs eat grass regularly, with only 8% showing illness before and 22% vomiting after.
Is it normal for dogs to eat grass?
Yes. A 2008 peer-reviewed study of 1,571 dog owners concluded that grass-eating is a normal behaviour unrelated to illness in the majority of cases. 68% of dogs eat grass daily or weekly. Only 8% showed prior signs of illness. The popular belief that dogs eat grass to vomit appears to be incorrect for most dogs.
Should I be worried if my dog eats grass?
Occasional casual grazing in a healthy dog with normal stools and appetite is not a concern. See your vet if grass-eating is urgent and compulsive, accompanied by frequent vomiting, loose stools, weight loss, reduced appetite, lethargy, or a swollen abdomen.
Do dogs eat grass because they are sick?
Not usually. Only 8% of dogs in large-scale survey research showed illness before eating grass. However, some dogs with specific gut conditions (acid reflux, IBD, bilious vomiting syndrome) do seek grass urgently as a response to discomfort. The distinction is urgency and the presence of other symptoms.
Do dogs eat grass because they have a nutritional deficiency?
Mixed evidence. Some dogs show reduced grass-eating when dietary fibre is increased. The large-scale survey found no significant difference between raw-fed, table-scrap-fed, and commercial kibble-fed dogs. A documented case of grass-eating resolving on a high-fibre diet suggests fibre deficiency can be a driver in some dogs, but is not the primary explanation for most.
Why do dogs eat grass and then vomit?
Dogs who showed illness signs before eating grass were more likely to vomit afterward. In these dogs, gut discomfort is the driver, the grass-eating follows from the discomfort, and vomiting follows from the combination of grass in an irritated gut. For most dogs who eat grass without prior illness signs, vomiting is uncommon.
How do I stop my dog from eating grass?
If behavioural: increase enrichment, mental stimulation, and interactive feeding. Redirect during walks. If dietary: add weekly green tripe for gut microbiome support, add sardines twice weekly for anti-inflammatory omega-3, and review overall diet quality. If accompanied by vomiting or gut symptoms: veterinary assessment first.
Is raw-fed dog grass-eating different from kibble-fed dog grass-eating?
Large survey research found no significant frequency difference between raw-fed and kibble-fed dogs. However, the specific drivers can differ. Raw-fed dogs with gut dysbiosis from an unbalanced or monotonous raw diet may show gut-discomfort-driven grass-seeking that raw-fed dogs with a balanced rotation including green tripe and oily fish typically do not.
Why do dogs eat grass? Most of the time, because they are dogs. The instinct is normal, the behaviour is common, and occasional casual grazing in an otherwise healthy dog is not a cause for concern. When grass-eating is urgent, compulsive, first-thing-in-the-morning behaviour with associated digestive symptoms, the dietary response is clear: raw green tripe weekly for gut microbiome and enzyme support, sardines twice weekly for anti-inflammatory omega-3, and a high-digestibility raw protein base like Primal Venison for clean colonic fermentation. Use the feeding calculator for daily amounts and the feeding guide for the full rotation protocol.
Rogue Raw Nutrition Team
NSW-based raw pet food specialists. This guide is general information, not veterinary advice. If your dog is showing signs of illness alongside grass-eating, always consult your veterinarian before making dietary changes. Over 30,000 Australian dogs fed.