Why Does My Dog Eat Grass? Is It Normal?

When to call your vet

Grass on its own is rarely the problem. Ring your vet if you notice:

• Desperate, gulping grass eating that is new for your dog, especially alongside drooling, swallowing hard or licking the floor
• Vomiting more than once, or vomiting with blood or dark, gritty material in it
• Retching without bringing anything up, or a belly that looks swollen or tight
• Your dog going off their food, seeming flat, or showing signs of tummy pain such as a hunched back or restlessness
• Diarrhoea, weight loss or a change in their stools that lasts more than a day or two
• Sneezing fits, pawing at the mouth or gagging after grazing, which can mean a grass seed or blade is stuck
• The chance they have eaten a treated lawn, garden plants or something else that could be poisonous

If anything about your dog worries you, a phone call to the practice is never a waste of their time.

How common is it?

Very. Vets and owners have long reported that grass eating is one of the most familiar things dogs do outdoors, and it is seen in dogs of every age, size and type. Puppies often try it as they explore with their mouths, and some adult dogs graze a little on most walks without any fuss at all.

A common belief is that dogs eat grass to make themselves sick. In reality, most dogs who eat grass do not vomit afterwards, and many show no sign of feeling unwell beforehand. Some dogs do bring grass back up, but it is not clear whether the grass caused the vomiting or whether a dog who already felt queasy happened to graze.

Possible reasons dogs eat grass

There is no single proven explanation, and different dogs may graze for different reasons. Ideas that vets and researchers have put forward include:

• They simply like it. Fresh spring grass seems to appeal to many dogs, who pick and choose particular blades or patches.
• Inherited behaviour. Wild canids are known to eat some plant material, so the habit may be part of a dog's natural repertoire rather than a sign of anything wrong.
• Boredom or something to do. Dogs left in a garden with little to occupy them may graze, chew or dig to pass the time.
• An upset stomach. Some dogs seem to eat grass more urgently when their tummy is unsettled. This is the pattern most worth noticing.
• Fibre or texture. It has been suggested that some dogs seek roughage, though this is not well proven.

Because the reasons are uncertain, the most useful thing you can do is watch how your own dog grazes. A relaxed nibble is very different from frantic gulping.

Calm grazing versus urgent grass eating

Usually fine	Worth watching or calling your vet
Slow, selective nibbling on walks	Rushing to eat large amounts as soon as they get outside
Dog is bright and eating normally	Dog is off their food, quiet or restless
No vomiting, or one small vomit of grass	Repeated vomiting, or vomit with blood
Has always grazed a little	A sudden new habit, or eating much more than usual
Normal stools	Diarrhoea, straining or mucus in stools

The real risks of eating grass

Grass itself is not toxic to dogs, but what is on it, in it or growing near it can be.

• Garden chemicals. Weedkillers, lawn feeds, fertilisers and slug pellets can all be harmful. Keep your dog off treated areas for as long as the product label advises, and be cautious on verges and in parks where you don't know what has been used.
• Slugs and snails. These can carry lungworm, a parasite that can make dogs seriously ill. Dogs can pick them up by eating grass, drinking from puddles or chewing toys left outside. Our page on lungworm in dogs explains the signs and how to protect your dog.
• Grass seeds and awns. In summer, sharp, arrow-shaped seed heads can lodge in the mouth, throat, nose or ears.
• Other plants. A grazing dog may also chew bulbs, leaves or toxic plants growing alongside the grass.
• Faeces and parasites. Grass in shared spaces may be contaminated with other animals' droppings, which can carry worms.

Practical steps if your dog loves grass

1. Keep up with parasite prevention. Ask your vet which worming and lungworm protection suits your dog and your area, and stick to the schedule.
2. Choose your grazing spots. If your dog is going to nibble grass, your own untreated lawn is safer than unknown verges.
3. Pick up toys and bowls at night. This reduces the chance of slugs and snails crawling over them.
4. Check after summer walks. Look between toes, in ears and around the mouth for grass seeds.
5. Add enrichment. Sniffing games, chews suitable for your dog, and short training sessions can satisfy dogs who graze out of boredom.
6. Look at the whole picture. If grass eating comes with tummy upsets, mention it to your vet rather than assuming it is the cause or the cure.

Avoid scolding your dog for grazing. If you would prefer they didn't, calling them away and rewarding them for coming back works better and keeps walks enjoyable.

Is my dog missing something in their diet?

This question comes up a lot. Dogs on a complete, balanced diet appropriate to their life stage should be getting the nutrients they need, and grass eating alone isn't a reliable sign of a deficiency. That said, if you have recently changed food, are feeding a home-prepared diet, or your dog also seems hungry all the time or is losing weight, it is worth discussing their diet with your vet. Our guide on how much to feed your dog is a good starting point.

Know your dog's grazing pattern

The pattern matters more than any single walk. A dog who has nibbled grass happily for years is not the same as one who suddenly starts gulping it down every morning. Jotting down when grass eating happens, alongside meals, any sickness and their energy that day, makes changes easier to spot. Petopedia lets you log food, water, weight and behaviour in one place, so if you do need to call your vet you can tell them exactly when it started and what else has changed. For other signs worth noting, browse the symptoms section.