Why Do Dogs Eat Grass?

Many dogs occasionally nibble on grass. This behaviour may seem concerning, but it’s usually normal. Let’s explore what researchers think is happening.

Common reasons dogs eat grass

Veterinarians haven’t pinned the behaviour on one single cause. Instead, several overlapping factors may explain why some pets can’t resist a mouthful of greenery:

Instinct and ancestry: Wild canines sometimes consume the stomach and intestines of herbivorous prey. Studies of wolves show that 11–47 % eat grass or other plants, so our dogs may have inherited a taste for vegetation.
Dietary fibre: Grass provides roughage. A lack of fibre can impair digestion, so some dogs nibble grass to help food move through the gut.
Nutrient deficiency or pica: Eating non‑food items is called pica and may occur when dogs have a nutritional gap or underlying medical issue. Well‑balanced diets make deficiencies rare, so speak to your vet if the behaviour is excessive.
Antacid for an empty stomach: Some dogs swallow grass then quickly vomit yellow bile. Vets believe eating a small meal or feeding a bedtime snack can prevent stomach acid irritation.
Boredom or anxiety: Dogs left alone may chew grass to pass the time or seek attention. Providing interactive toys and more exercise can reduce this behaviour.
Taste and texture: Fresh, dewy grass may simply be appetising or fun to chew.

Theories & evidence

There is no single, proven reason why dogs eat grass. Veterinary behaviourists speculate that dogs may eat grass to induce vomiting, soothe an upset stomach, add fibre to their diet or simply because they enjoy the texture. Research suggests that dogs typically eat grass before meals and less often after eating, hinting that hunger or instinct may play a role.

Do dogs eat grass to make themselves vomit?

Contrary to popular belief, most dogs do not vomit after eating grass. Studies show that fewer than 25 % of dogs vomit after eating grass. Therefore, vomiting is unlikely to be the primary reason for grass consumption.

Is grass eating dangerous?

Occasional grass eating is generally harmless, but there are risks. Lawns treated with pesticides or herbicides can be toxic. Avoid letting your dog graze in areas that may have been treated, and prevent them from eating unknown plants.

When to call the vet

Your dog eats grass excessively and vomits repeatedly.
Grass eating is accompanied by lethargy, appetite loss or other signs of illness.
You suspect your dog ingested a toxic substance.

How to stop your dog from eating grass

Grazing is usually harmless, but if you’d rather your pup focus on something else, try these veterinarian‑approved strategies:

Feed a balanced, high‑fibre diet: Talk to your vet about whether your dog needs more fibre. Switching foods or adding a vet‑approved fibre supplement can reduce grazing.
Boost mental stimulation: Provide chew toys, treat‑dispensing puzzles and training games to keep your dog occupied and relieve anxiety. See our recommended interactive toy below.
Increase exercise and attention: Dogs that get regular walks and play sessions are less likely to eat grass out of boredom.
Use positive reward training: Redirect your dog when they start to nibble grass and reward them for focusing on you or performing a trick.
Avoid treated lawns: Keep pets away from areas that may have been sprayed with herbicides or pesticides and always supervise if you’re unsure.

Editors’ choice interactive toy

KONG Classic Dog Toy – Durable natural‑rubber toy that bounces unpredictably and can be stuffed with treats to keep dogs mentally stimulated and reduce boredom.

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More behaviour insights

Explore related behaviour guides:

Why dogs eat poop – coprophagia explained.
Why dogs chew furniture – underlying causes of destructive chewing.
Why dogs bark – understand different types of barking and how to manage them.

Last updated: March 2026.