Why Is My Dog Eating Grass and Vomiting?

Most dogs eat grass. Most of them are fine. The internet has convinced a generation of owners that it always means nausea, and that is not what the evidence suggests — plenty of dogs graze happily and never vomit at all.

The common, boring reasons

• They like it. New spring growth is sweet, and grazing is a normal canine behaviour observed in wild canids too.
• Boredom. A dog alone in a yard with nothing to do will find something to chew.
• Fibre. Some dogs seem to seek roughage, particularly if their diet is low in it.
• Nausea, sometimes. A dog that suddenly eats grass frantically and then vomits may well have felt sick first.

When it is worth a vet visit

Frequency and pattern matter more than the behaviour itself. Book an appointment if you see repeated vomiting over more than a day, blood in the vomit, weight loss, a change in appetite, lethargy, or a dog that has suddenly started grazing obsessively when it never did before. Sudden new behaviour in an older dog is always worth a look.

Retching without producing anything, especially in a large deep-chested breed with a swollen belly, is an emergency — that can be bloat and it is measured in hours.

The South African wrinkle

What is in the grass matters more here than the grass itself. Snail bait pellets scattered on lawn, recently applied herbicide or fertiliser, and blackjacks and grass seeds that lodge in the throat are all common. A dog that grazes is also a dog that eats whatever the garden service sprayed that morning — ask them to tell you before they treat, and keep dogs off for the interval on the label.

If you want to reduce it

Add a walk, add a food puzzle, add a chew. Most compulsive grazing in an otherwise healthy dog is an occupation problem. Grow a pot of pet-safe grass if your dog clearly enjoys it — cat grass works fine for dogs and gives them somewhere safe to indulge.