Why does my dog eat grass? What the research actually says
Watching a dog graze on the lawn mid-walk worries plenty of owners, who often assume it's a sign of a digestive problem. Two behavioral studies specifically set out to check whether that explanation holds up. All our guides are gathered in the dog care and grooming section.
Is the behavior really that common?
A study by Sueda, Hart and Cliff, published in 2008 in Applied Animal Behaviour Science, surveyed owners of dogs with daily access to plants and found that 79% of them reported grass or other plant-eating behavior (study on Google Scholar). Only a minority of the dogs involved appeared ill beforehand, and an even smaller minority vomited afterward: the behavior is therefore mostly normal rather than a systematic warning sign.
Is the link with vomiting confirmed elsewhere?
An Australian study by Bjone, Brown and Price, published in 2007 in the proceedings of Rural and Regional Advances in Animal Nutrition, analyzed grass-eating habits in a sample of pet dogs and likewise concluded that the behavior occurs in otherwise healthy animals, with no systematic link to a dietary deficiency (study on Google Scholar).
So why does a dog eat grass?
- Exploratory behavior: chewing and tasting plants is part of the dog's natural repertoire, inherited from ancestral opportunistic-omnivore behavior.
- Sensory appeal: the texture and taste of fresh grass simply seem pleasant to some dogs, with no particular digestive motivation.
- Boredom or lack of stimulation: an under-stimulated dog on a walk may turn to vegetation for lack of anything else to do, a case where a snuffle mat or a chew toy often makes a real difference.
When should you actually worry?
Sudden, excessive grass eating combined with lethargy, repeated vomiting or loss of appetite warrants a vet visit: these signs go beyond the normal behavior described in the studies. A chemically treated lawn or an accidentally ingested toxic plant also call for immediate caution.
Should you stop your dog from eating grass?
No, unless the area is treated or a risky plant is involved: a dog that occasionally grazes on a healthy lawn shows no particular danger according to the available data.
Frequently asked questions
Does eating grass mean a dietary deficiency?
Available studies do not confirm this link: most dogs that graze are fed normally and show no signs of deficiency.
Does the dog always vomit after eating grass?
No, only a minority of episodes end in vomiting according to the data collected from owners.
Can a puppy eat grass safely?
Generally yes, as long as any chemical lawn treatment and nearby toxic plants are ruled out. Find all our guides on the dog hub.
This guide is part of Planète Pets’s Dogs universe. Our advice is general in nature: for any health concern, your veterinarian remains the only reference.