Important Medical Disclaimer: This article is educational and based on veterinary guidelines. If your dog eats grass excessively, vomits repeatedly, shows signs of distress, or has diarrhea that lasts more than a day, consult your veterinarian. Occasional grass eating is normal, but persistent or unusual behaviour warrants professional attention.
You're out for a walk and your dog suddenly drops their nose to the ground and starts grazing like they've completely forgotten they're a dog. It's one of those things that catches first-time owners off guard, and even experienced dog owners sometimes find themselves wondering whether to be worried. The short answer is: probably not. Studies suggest that up to 80% of dogs eat grass at some point, making it one of the most common behaviours vets are asked about.
That doesn't mean it's always nothing. Understanding why dogs eat grass, when it's harmless and when it isn't, helps you respond with the right level of concern rather than either panicking or ignoring something worth checking.
Why Do Dogs Eat Grass?
No single explanation covers every dog, and that's part of what makes this behaviour so interesting. Researchers and veterinarians have identified several reasons dogs eat grass, and for most dogs it's a combination of factors rather than one clear cause.
It's Instinctive Behaviour
Dogs are descended from omnivores who ate plant material as part of their natural diet. Wild canids regularly consume the stomach contents of their prey, which often includes grass and other vegetation. For domestic dogs, grazing may simply be an expression of that deep-rooted instinct, something their biology still drives them toward even when it serves no obvious nutritional purpose.
This helps explain why some dogs eat grass calmly and methodically, without any apparent distress before or after. For these dogs, it appears to be a behaviour they enjoy rather than a symptom of anything wrong.
They Simply Like It
This one surprises people, but many dogs enjoy the taste and texture of certain grasses, particularly fresh, young shoots in spring and early autumn. A friend of ours has a dog who grazes enthusiastically in the garden most mornings and also steals vegetables off the kitchen counter whenever she gets the chance. Her owner joked that they weren't sure if they had a dog or a small sheep. The vet, when asked, was reassuringly unbothered. Some dogs just find plants appealing, and there's nothing inherently wrong with that.
Digestive Discomfort
This is the explanation most people reach for first, and it does apply in some cases. Dogs with mild stomach upset sometimes eat grass and vomit shortly afterward, which may help them relieve the discomfort. However, research suggests that vomiting after eating grass is actually less common than most people assume. Only around a quarter of grass-eating dogs vomit afterward, which means most are eating grass for other reasons entirely.
If your dog eats grass and then vomits regularly, it's worth looking at their diet more closely. Speed eating is a significant contributor to digestive upset in dogs. A dog who inhales their food creates excess gas and puts stress on the stomach, which can trigger the kind of low-level discomfort that leads to grass eating. Slowing down mealtimes addresses the root cause rather than just the symptom. The Ceramic Slow Feeder Bowl with Acacia Wood Stand is designed for exactly this, encouraging dogs to eat at a healthier pace while the elevated acacia wood stand supports better posture during meals.
Boredom and Under-Stimulation
Dogs who don't get enough mental stimulation often develop repetitive behaviours, and grass eating is one of them. A dog who spends a lot of time in the garden without much to do may graze simply because it's something to do. If you notice your dog eats grass mostly during quiet periods or when they seem restless, boredom is likely a significant factor.
When Should You Be Concerned?
Most grass eating is harmless, but there are situations that deserve more attention. If your dog eats grass frantically rather than calmly, urgently and repeatedly, this can signal more significant digestive distress than the casual grazing most dogs do. Frantic eating followed by repeated vomiting, particularly if your dog also seems lethargic or their abdomen looks distended, warrants a call to your vet.
Watch for what else is happening alongside the grass eating. Blood in the vomit or stool, signs of pain when the abdomen is touched, or a sudden change in eating patterns more broadly are all reasons to seek veterinary advice rather than waiting to see how things develop.
Pesticides and herbicides on grass are also worth thinking about. If your dog grazes in areas that may have been treated, this is a genuine risk. Garden grass you manage yourself is generally safer, but public parks, roadsides, and other people's gardens are less predictable. Rinse your dog's muzzle after walks where they've been grazing in unknown areas, and redirect the behaviour in treated spaces.
How to Reduce Grass Eating If It's Becoming a Habit
If your dog's grass eating feels excessive or you'd simply prefer to redirect the behaviour, the most effective approach targets the underlying cause rather than just stopping the behaviour itself.
For dogs who eat grass out of boredom, increasing mental stimulation makes a significant difference. Sniff work is one of the most effective forms of mental exercise for dogs, engaging the same problem-solving and focus that a long physical run does, often with a calmer result afterward. The Nomi Woodland Adventure Snuffle Mat offers exactly this kind of enrichment at home. At 154 x 97 cm with multiple hiding zones, squeaky toys, and varied textures, it gives dogs a genuine foraging challenge that satisfies the same instinct that sends them toward the grass in the first place. For dogs who graze in the garden out of habit, a snuffle mat session before outdoor time often reduces the behaviour noticeably.
For dogs who seem to eat grass because of digestive discomfort, reviewing their diet, feeding schedule, and eating pace is the most productive starting point. Consistent meal times, appropriate portion sizes, and slowing down fast eaters addresses the source of discomfort at its root.
Teaching a reliable "leave it" command gives you a practical tool for redirecting grass eating in the moment, and it's a useful skill across many situations. Practice in low-distraction settings first and gradually work up to using it outdoors. Our guide on raising a puppy covers how to build these foundational commands from an early age.
Frequently Asked Questions
Is it normal for dogs to eat grass every day? Daily grass eating is common in many dogs and is usually not a cause for concern on its own. If it's calm and your dog seems otherwise healthy and comfortable, it's likely habitual or enjoyment-based rather than a sign of a problem.
Should I stop my dog from eating grass? Not necessarily. If the grass is unsprayed and your dog isn't vomiting or showing distress, there's no urgent reason to stop them. If it's excessive, frantic, or followed by repeated vomiting, redirecting the behaviour and checking with your vet is sensible.
Can eating grass make my dog sick? Grass itself is not toxic to dogs. The main risks are pesticide or herbicide contamination, and the possibility that repeated vomiting indicates underlying digestive discomfort worth investigating.
Why does my dog eat grass and then vomit white foam? White foam vomit after eating grass often indicates the stomach was empty when the grass was eaten, and can also suggest mild acid reflux or gastric irritation. If it happens occasionally it's usually not serious; if it happens regularly, speak to your vet.
Do dogs eat grass because they're missing something in their diet? Nutritional deficiency is sometimes suggested as a cause, but research doesn't strongly support this for most dogs on complete, balanced diets. If you're concerned about your dog's nutrition, a conversation with your vet about their current food is the best starting point.
Most dogs who eat grass are simply being dogs. The behaviour is rarely a sign of something wrong, and in most cases it doesn't need to be stopped. Knowing what to watch for, and recognising when the calm grazing you're used to starts looking different, is what matters most.
Bronnen:
Sueda, K. L. C., Hart, B. L., & Cliff, K. D. (2008). Characterisation of plant eating in dogs. Applied Animal Behaviour Science, 111(1–2), 120–132. Retrieved from https://doi.org/10.1016/j.applanim.2007.05.018
American Kennel Club. (n.d.). Why do dogs eat grass? Retrieved from https://www.akc.org/expert-advice/health/why-do-dogs-eat-grass/
VCA Animal Hospitals. (n.d.). Grass eating in dogs. Retrieved from https://vcahospitals.com/know-your-pet/grass-eating-in-dogs
Merck Veterinary Manual. (n.d.). Pica in dogs. Retrieved from https://www.merckvetmanual.com/dog-owners/digestive-disorders-of-dogs/pica-in-dogs