What this means
Dogs eat grass for various reasons, and not all of them are understood. For many it is simply a habit or boredom, but sometimes grass-eating is linked to an upset digestive system. The grass-eating itself does not show which reason is the real one.
Note whether your dog eats grass calmly, picking it out, or greedily and in a rush, whether it vomits afterwards, whether the grass passes in the stool and whether appetite or weight changes at the same time. Also notice whether your dog is grazing where the grass may have been sprayed or fertilised.
It is also worth remembering that grass can be sprayed with chemicals and some plants are poisonous. If you suspect your dog ate an unknown plant or sprayed grass, do not wait for signs to appear.
Possible causes
These are things that can cause this sign. It is not a diagnosis, and they are not equally likely for your dog.
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Habit, boredom or curiosity
Many healthy dogs eat grass out of habit or simply because it is interesting. Your dog is bright, eats and behaves as usual.
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An irritated stomach
Some dogs eat grass greedily before or after feeling unwell in the stomach and sometimes bring it back up. It is usually a short-lived episode.
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Intestinal inflammation
Long-term inflammation of the gut can show as frequent grass-eating alongside vomiting, diarrhoea or changes in appetite.
About the condition: Inflammatory bowel disease (IBD) -
Inflammation of the pancreas
An inflamed pancreas causes nausea, vomiting and belly pain. Your dog may eat grass and also seem flat or stand stretched out.
About the condition: Pancreatitis -
Too many bacteria in the small intestine
When the small intestine holds too many bacteria, gas, diarrhoea and other digestive signs may appear, and grass-eating can be one of them.
About the condition: Small intestinal bacterial overgrowth (SIBO)
What else to watch for
These observations help your vet build the picture faster. Note down what you saw and when.
- Whether your dog eats grass calmly, or greedily and in a rush
- Whether it vomits afterwards and whether there is grass in the vomit
- Whether appetite or weight changed
- Whether the stools changed
- Whether your dog seems flat or sore at the same time
- Where your dog eats grass, and whether it may have been sprayed
When to book a routine visit
Book a visit if your dog suddenly eats a lot of grass or does so every day, or if it comes with vomiting, diarrhoea, weight loss or changes in appetite. If any of the urgent signs above appear, go straight away rather than waiting for an appointment.
Related conditions
Conditions whose entries mention this sign. The list is somewhere to read on, not a way to reach a diagnosis.
- Inflammatory bowel disease (IBD) Digestion and liver This is a long-term disorder of the digestive tract in which inflammatory cells build up in the wall of the stomach or intestine, so it becomes less able to digest food and absorb nutrients. The exact cause is not fully understood; an interplay between the immune system, gut bacteria and food is thought to play a part. Because many other digestive problems look much the same, a vet works out what is really going on with tests.
- Pancreatitis Digestion and liver Pancreatitis is inflammation of the pancreas, in which digestive enzymes become active too early and start to irritate the pancreas itself and the tissue around it. It can come on suddenly or smoulder for a long time with repeated flare-ups, and in more severe cases it affects other organs too. The causes vary, so working out what is going on with a particular dog is a job for the vet.
- Small intestinal bacterial overgrowth (SIBO) Digestion and liver This is a condition in which too many bacteria, or the wrong kinds, take hold in the small intestine. They compete with the dog for nutrients and irritate the gut wall, so food is digested and absorbed less well. It can be the result of another intestinal or pancreatic problem, so a vet also looks for the underlying cause.
Body systems: Digestion and liver