🌱 The lawn snack
Why Does My Dog Eat Grass?
The common explanation turns out to be the one the evidence least supports.
What the research found
The sickness theory says dogs eat grass deliberately to induce vomiting. Survey work at UC Davis tested it and found the opposite pattern: grass-eating was extremely common — the large majority of dogs with regular outdoor access did it — while vomiting afterwards was uncommon, reported in well under a quarter of cases.
More to the point, few owners reported signs of illness before the grass-eating. If the behaviour were a deliberate remedy, you would expect sick dogs first and grass second. Mostly you get healthy dogs eating grass and carrying on with their day.
The likelier explanations
It is normal canine behaviour. Wild canids eat plant material routinely; analyses of wolf scat find grass in a meaningful share of samples. Dogs are not obligate carnivores and never were.
It tastes and feels interesting. Fresh spring grass is sweet, and the texture is novel. Plenty of dogs are selective about which grass, which points at palatability rather than medicine.
Boredom. A dog in a garden with nothing to do will investigate what is there, and grass is what is there.
Possibly fibre. A plausible but not well-established idea; some dogs with low-fibre diets reduce grass-eating when fibre increases.
When it does matter
The behaviour itself is usually fine. The context sometimes is not. Take notice if grass-eating is frantic and new — gulping large amounts urgently, especially with lip-licking, drooling or repeated swallowing — which can indicate nausea or reflux. A sudden change in a long-standing pattern is more informative than the behaviour itself.
Also worth attention: grass-eating that comes with vomiting more than occasionally, weight loss, or a change in appetite. That is a vet conversation.
The real risk is what is on the grass
This is the part that genuinely matters. Lawn treatments — herbicides, fertilisers, slug pellets — are far more dangerous than the grass. Metaldehyde slug bait is lethal to dogs in small quantities.
Grass also carries lungworm, picked up from slugs and snails that leave trails across it, which is serious and in some regions common. And long tough grass seeds can lodge in the throat or work into the skin.
So: know what has been sprayed on any lawn your dog grazes, keep parasite prevention current, and if you want to offer a safe outlet, a tray of untreated cat grass costs almost nothing.
Quick answers
Do dogs eat grass to make themselves sick?
The evidence does not support it. Survey research found grass-eating is very common while vomiting afterwards is not, and most dogs showed no signs of illness beforehand.
Should I stop my dog eating grass?
The behaviour itself is normal. What matters is what is on the grass — herbicides, fertilisers and slug pellets are genuinely dangerous, and slug trails carry lungworm.
When is grass-eating a warning sign?
When it is sudden, frantic and paired with drooling, lip-licking or repeated swallowing, which can indicate nausea or reflux. A marked change from the usual pattern is the thing to watch.