Dog Behavior
Why Do Dogs Eat Grass? Is It Normal and When to Worry
Why do dogs eat grass? Grass eating is very common and, for most dogs, normal. Many dogs simply seem to like it, and others do it out of boredom or to add a little roughage. It isn't usually a sign of illness, but a sudden change, frantic grass eating, or grazing followed by repeated vomiting is worth a call to your vet.
Is it normal for my dog to eat grass?
Yes. Vets see grass eating as a common dog behaviour, and the American Kennel Club describes it as normal for many dogs. A popular belief is that dogs eat grass to make themselves sick, but research led by vets at UC Davis found that most grass-eating dogs didn't seem unwell beforehand and most didn't vomit afterwards.
Why does my dog eat grass? Likely reasons
| Reason | What it looks like | What helps |
|---|---|---|
| They like it | Calm, selective nibbling of fresh spring grass | Nothing, if the grass is untreated |
| Boredom | Grazing when left alone in the garden or on dull walks | More play, sniffing walks and puzzle feeders |
| Instinct | Wild relatives ate plant matter too | Nothing; it's natural behaviour |
| Wanting more fibre | Regular grazing, sometimes with soft stool | Ask your vet whether the diet suits your dog |
| Upset stomach | Sudden, urgent gulping of grass, licking lips, then vomiting | Call your vet if it repeats or your dog seems unwell |
| Attention | Eats grass when you're watching, then looks at you | Ignore it and reward calm behaviour |
When to worry about your dog eating grass
Call your vet if your dog:
- Suddenly starts eating lots of grass when they never did before
- Eats grass frantically and vomits repeatedly
- Has diarrhoea, blood in the stool or vomit, or a swollen or painful belly
- Is lethargic, off their food, or losing weight
- Also eats soil, stones, fabric or other non-food items
How to keep grass eating safe
- Avoid treated grass. Pesticides, herbicides and fertilisers can be harmful. Keep dogs off lawns that have been sprayed.
- Know your plants. Some garden plants are toxic to dogs; check anything your dog chews.
- Keep parasite prevention up to date. Grass outdoors can carry parasite eggs from other animals' faeces.
- Watch for long blades or grass seeds. Grass awns can lodge in the mouth, nose or throat.
- Grow dog-safe grass indoors (such as wheatgrass) if your dog loves to graze.
How to stop a dog eating grass
- Add more exercise, sniffing time and play.
- Bring a toy or chew on walks to redirect them.
- Teach a solid "leave it" and reward it every time.
- Use a lead in areas where grass may be treated.
- Ask your vet about diet if grazing is constant.
For more ideas to keep your dog busy, see mental stimulation for dogs and is my dog bored?
Frequently asked questions
Why does my dog eat grass and then throw up?
Some dogs vomit after eating grass, possibly because the grass tickles the throat or stomach. Most grass-eating dogs don't vomit. If it happens often, or your dog seems unwell, see your vet.
Should I stop my dog from eating grass?
Occasional grazing on untreated grass is usually fine. Stop it if the grass may be sprayed, if your dog eats a lot, or if it leads to vomiting.
Do dogs eat grass when they are sick?
Sometimes, but research suggests most dogs that eat grass don't show signs of illness beforehand.
Why does my dog eat grass every morning?
It may be habit, enjoyment or an empty stomach. If it comes with vomiting yellow bile, ask your vet whether a small late-evening meal could help.
Why do cats eat grass?
Cats also nibble grass, and many enjoy cat grass grown indoors. As with dogs, frequent vomiting or a change in behaviour is worth a vet check.
Sources
Guidance follows the American Kennel Club and the ASPCA Animal Poison Control Center. This article is general information, not veterinary advice.
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