Why does my dog eat grass?
Usually normal. Occasionally a signal. Almost never the sickness cure people assume.
The theory most people believe
That dogs eat grass to make themselves sick. Surveys of owners suggest otherwise: the large majority of dogs that eat grass do not vomit afterwards, and most show no signs of illness beforehand. Where vomiting does follow, it is more plausibly the result of the grass than the reason for it.
More likely explanations
It is normal dog behaviour. Wild canids consume plant material regularly. Grass-eating shows up in dogs of every age and health status.
Fibre. Some dogs seem to seek roughage, and cases exist where increasing dietary fibre reduced the behaviour.
Boredom. Dogs left in a garden with nothing to do investigate what is available, and grass is available.
Taste and texture. Fresh spring growth is sweeter, which is why the behaviour often spikes in spring.
The actual risk is not the grass
- Lawn treatments — herbicides, pesticides and fertilisers on your grass or a neighbour's
- Slug pellets — metaldehyde poisoning is a genuine emergency
- Lungworm — spread by slugs and snails on grass, potentially fatal, preventable with the right wormer
- Grass seeds in summer — awns work into paws, ears and eyes and often need surgical removal
When to see a vet
Sudden frantic grass eating in a dog that never did it before, particularly with lip licking, drooling, restlessness or repeated unproductive retching, warrants a same-day call. In deep-chested breeds those signs can indicate bloat, which is life-threatening and progresses within hours.
Also worth investigating: grass eating alongside weight loss, appetite change, or chronic vomiting and diarrhoea, which can point to gastrointestinal disease.
If you want to reduce it
Rule out medical causes first, then look at enrichment — more sniffing walks, puzzle feeders, training sessions. Consider whether the diet provides enough fibre, and ask your vet about lungworm cover, which is worth having in any case if your dog grazes.
Get an accurate daily portion
Enter weight, life stage and your food's calorie content for grams per day and per meal.
Open the food calculator →Grass itself is usually harmless. What matters is what else is within reach in the garden and the kitchen. Toxic foods for dogs →
Common questions
Is it bad for dogs to eat grass?
Grass itself is generally harmless. The risks come from what is on it — lawn chemicals, slug pellets, and lungworm carried by slugs and snails — and from grass seeds in summer, which can work into paws and ears.
Do dogs eat grass to make themselves sick?
The evidence does not support it. Most dogs that eat grass do not vomit afterwards and show no signs of illness beforehand.
When should I worry about grass eating?
If it starts suddenly and frantically, especially with drooling, restlessness or unproductive retching, contact a vet the same day. In deep-chested breeds those signs can indicate bloat.