Dogs can eat grass, and it’s usually normal, but there are a few situations where it can signal a problem or be unsafe.

Quick Scoop: Is it safe?

  • Plain, untreated grass is generally considered harmless for most healthy dogs when eaten occasionally.
  • The bigger risks come from:
    • Lawns treated with pesticides, herbicides, or fertilizers.
* Parasites like worms, lungworm, or other organisms on the grass.
  • Call your vet promptly if grass-eating is followed by repeated vomiting, lethargy, diarrhea, or refusal to eat normal food.

Why dogs eat grass (main theories)

Experts don’t agree on a single reason, but several well-supported ideas keep coming up.

1. They just like it

  • Many dogs simply like the taste or texture of grass, especially when it’s fresh and young in spring or summer.
  • Surveys suggest a large percentage of dogs eat plants (mostly grass) periodically, even when they seem perfectly healthy.

2. Natural instinct

  • Wild canids (like wolves) get plant material from the stomachs of their herbivorous prey, so eating grass may be an inherited instinct to include some rough plant matter in the diet.
  • Some vets and behaviorists see grass-munching as a leftover instinct rather than a sign something is “wrong.”

3. Fiber and diet gaps

  • Grass is roughage: it provides fiber that can help digestion and bowel movements.
  • One case report found a dog that ate grass and vomited daily stopped the behavior after being switched to a higher-fiber diet, suggesting diet can play a role.
  • Dogs with low-fiber or poorly balanced diets may turn to grass to “top up” what they’re missing.

4. Upset stomach or nausea

  • Some dogs eat grass when they have an upset stomach, diarrhea, or nausea, and may vomit shortly afterward; owners often notice this pattern.
  • Grass can act mechanically (irritating the stomach or throat) and help induce vomiting, which might relieve discomfort.
  • But research and owner surveys suggest most dogs that eat grass do not show clear signs of stomach upset beforehand, so this is not the only explanation.

5. Boredom, attention, or stress

  • Chewing grass can be a boredom behavior when dogs aren’t mentally or physically stimulated enough.
  • Some dogs may use it as a way to get their owner’s attention if it reliably triggers a reaction.

When you should worry

Watch how often and how intensely your dog eats grass, and what happens afterwards.

Call or visit your vet if:

  1. Your dog prefers grass over regular food or suddenly refuses their normal diet but still eats grass.
  1. Grass-eating is excessive, obsessive, or new for your dog.
  1. Vomiting happens multiple times within a few hours after eating grass, or there’s blood in vomit or stool.
  1. There are other symptoms: weight loss, diarrhea, lethargy, drooling, abdominal pain, or “off” behavior.
  1. You know or suspect the grass was treated with chemicals, or there is risk of lungworm (slugs/snails in the area).

In rare cases, long strands or clumps of grass can cause obstructions or get stuck and create more serious issues, which is another reason to check in with a vet if something seems off.

Simple steps to keep it safe

If your dog occasionally nibbles grass and seems otherwise fine, these steps can reduce risk.

  • Choose safe areas
    • Avoid lawns treated with fertilizer, pesticides, or herbicides.
    • Be cautious in areas with many slugs and snails (lungworm risk).
  • Keep up with parasite prevention
    • Regular deworming and vet-recommended parasite control help protect dogs that chew on grass and other outdoor surfaces.
  • Check and adjust diet
    • Ask your vet whether your dog’s food provides enough fiber and is nutritionally complete.
* For some dogs, a higher-fiber or better-balanced diet reduces grass-seeking.
  • Add enrichment
    • More walks, sniffing time, puzzle feeders, and play can reduce boredom-driven grass chewing.
  • Train an “off the grass” cue
    • You can teach a cue like “leave it” and reward your dog for ignoring grass, especially in high-risk areas.

Mini FAQ (forum-style)

“My dog eats grass then throws up – is that normal?”

  • It’s a fairly common pattern and not automatically an emergency, but frequent or repeated vomiting, or any other worrying signs, should be checked by a vet.

“Does eating grass mean my dog is sick?”

  • Not necessarily; many healthy dogs eat grass with no other symptoms.
  • It can, however, be one sign among others of stomach upset, parasites, or diet issues, so context matters.

“Should I stop my dog from eating grass?”

  • Occasional grazing on safe, untreated grass in a healthy dog usually doesn’t need strict policing.
  • You should prevent it if the area is treated with chemicals, your dog gets sick afterward, or the behavior is obsessive or new.

Bottom note

Information gathered from public forums or data available on the internet and portrayed here.