If your dog is eating grass and being sick, you’re not alone in wondering whether this behavior is normal or a sign of something serious. Many dog owners report seeing their dogs munch on grass only to vomit shortly afterward.
This combination of symptoms can point to several underlying causes.
We outline why dogs eat grass, what it means when they vomit afterward, and when to seek veterinary care.
Table of Contents
Dog Eating Grass and Being Sick: Why It Happens
When a dog eats grass and then becomes sick, especially vomiting shortly afterward, it’s often because the dog is trying to relieve an upset stomach or nausea. Eating grass can irritate the stomach lining, prompting vomiting that helps the dog feel better temporarily.
While occasional grass eating followed by mild sickness can be normal, frequent or severe vomiting may indicate underlying issues such as gastrointestinal infections, dietary problems, parasites, or even poisoning.
Dog Eating Grass and Being Sick: Common Causes
1. Gastrointestinal Infections
Viruses, bacteria, or parasites can all upset your dog’s digestive system.
When your dog is feeling unwell, eating grass and vomiting might be their body’s response to irritation or infection.
These infections can lead to nausea, and the grass acts as a natural way for dogs to purge their system.
However, this isn’t a cure and may make things worse if left untreated.
Related: Dog eating grass and not eating (Here’s why)
2. Dietary Indiscretion
Dogs love to explore the world with their mouths. Sometimes they eat garbage, spoiled food, or even toxic substances like chocolate or plants.
This “dietary indiscretion” can upset their stomach, leading to a dog eating grass and being sick.
3. Food Allergies or Intolerance
If your dog recently changed diets or started a new brand of dog food, they may react poorly to new ingredients.
Some dogs develop sensitivities to grains, beef, chicken, or artificial additives.
This can cause stomach upset, leading to grass consumption followed by vomiting.
4. Parasites
Intestinal parasites such as roundworms, hookworms, or giardia can irritate your dog’s digestive tract.
Dogs may eat grass as a response to the discomfort, which leads to vomiting.
If your dog is eating grass and also shows signs of weight loss, bloated belly, or loose stool, a fecal test may be needed.
5. Toxin Ingestion
If your dog has ingested a toxic substance—such as a household cleaner, pesticide-treated grass, or poisonous plant—they may eat grass and vomit as their body tries to expel the toxin.
This is a medical emergency. If your dog ate grass and is now vomiting repeatedly or shows signs like shaking, panting, or unresponsiveness, seek emergency veterinary care immediately.
Related: Dog eating grass and coughing (Here’s why)
Dog Eating Grass and Throwing Up Foam
A dog that eats grass and throws up foam is often experiencing stomach irritation or nausea. The foam is usually a mixture of saliva and stomach acid, particularly if the stomach is empty.
Some dogs eat grass shortly before vomiting, possibly because they feel nauseated or because the grass helps trigger the vomiting reflex.
Occasional episodes may not be serious, but repeated grass eating and foamy vomiting can indicate digestive disease, dietary issues, or another health problem.
Veterinary evaluation is required if the episodes become frequent or are accompanied by other symptoms.
Puppy Eating Grass and Being Sick
A puppy that is eating grass and then becoming sick may be experiencing digestive upset, dietary intolerance, parasites, or irritation of the stomach.
Puppies sometimes eat grass out of curiosity, but repeated grass eating followed by vomiting or signs of illness suggests that something may be upsetting the digestive system.
Because puppies have developing immune systems and can become dehydrated quickly, ongoing symptoms should be taken seriously.
If the puppy continues vomiting, develops diarrhea, becomes lethargic, or refuses food, veterinary attention is recommended to identify the cause and prevent complications.
Old Dog Eating Grass and Being Sick
An older dog that eats grass and then becomes sick may be trying to cope with nausea or stomach discomfort.
Senior dogs are more likely to have underlying health conditions such as gastrointestinal disease, kidney disease, liver disease, or other age-related illnesses that can cause nausea and trigger grass eating.
While occasional grass consumption is common, repeated episodes accompanied by illness are more concerning in older dogs.
If the dog is vomiting, losing weight, refusing food, or showing reduced energy levels, a veterinary examination is important to determine whether an underlying medical condition is responsible.
How to Handle a Dog Eating Grass and Being Sick
If your dog eats grass occasionally and throws up once in a while, it may not require urgent medical attention.
However, here’s what you can do:
1. Monitor Behavior Closely
Note the frequency and circumstances of the dog eating grass and being sick.
Is it after meals? During walks? When stressed? Keeping track helps you identify patterns.
2. Check Their Diet
Ensure your dog’s food is high in fiber, balanced in nutrients, and free from ingredients they may be intolerant to.
You may also consider switching from dry to wet food if hydration is an issue.
3. Reduce Access to Treated Lawns
If your dog eats grass during walks or in your yard, make sure the area is free from pesticides, herbicides, or fertilizers.
Ingesting treated grass can cause poisoning.
4. Provide Mental Stimulation
Boredom can lead to grass eating. Make sure your dog gets enough exercise, toys, and interaction to reduce stress or idle behavior.
5. Visit a Veterinarian
If vomiting continues or is accompanied by other symptoms like diarrhea, lethargy, or poor appetite, schedule a vet visit.
They may perform diagnostic tests such as blood work, fecal exams, or X-rays.
When to See the Vet Immediately
You should seek veterinary care if your dog is eating grass and being sick, and if the following happens:
Vomiting more than once a day
Presence of blood in vomit or stool
Refusal to eat or drink
Signs of dehydration (dry gums, sunken eyes)
Seizures or collapse
Symptoms persisting for more than 24 hours
Young puppies and senior dogs are especially vulnerable and should be examined sooner rather than later.
Dog Eating Grass and Being Sick: Treatment
Treatment depends on the underlying reason the dog is eating grass and becoming sick.
The veterinarian may perform an examination and recommend tests to check for parasites, gastrointestinal disease, dietary intolerance, or other medical conditions.
Treatment may include dietary changes, anti-nausea medication, deworming, probiotics, or treatment for any identified illness.
At home, ensuring your dog stays hydrated and avoiding sudden diet changes can help support recovery.
Key Takeaway
A dog eating grass and being sick can be a puzzling behavior, but it’s not always a cause for alarm.
While some dogs simply like the taste or texture of grass, vomiting afterward suggests a deeper reason, such as nausea, digestive upset, or even an underlying illness.
Keep an eye on your dog’s behavior, monitor how often it happens, and look for any additional symptoms.
If the issue becomes frequent or is accompanied by other concerning signs, don’t hesitate to consult your veterinarian.
By addressing the root cause and taking proactive steps, you can help keep your dog happy, healthy, and free from the cycle of grass-eating and vomiting.