If your dog is eating grass and vomiting, it’s natural to feel concerned. Many pet parents worry when their dog suddenly starts munching on the lawn, only to throw up afterward.
While this behavior might seem odd or alarming, it’s actually more common than you may think.
Understanding why dogs eat grass and vomit is essential to determining whether it’s a harmless quirk or a symptom of an underlying issue.
We outline the reasons behind dog eating grass and vomiting, what it means, and when to seek veterinary care.
Table of Contents
Here’s Why Dog Eating Grass and Vomiting Happens
When a dog is eating grass and vomiting, it is often a sign that the dog is trying to relieve an upset stomach or nausea. Eating grass can irritate the stomach lining, which may trigger vomiting to help expel whatever is causing discomfort, such as indigestion, dietary indiscretion, or mild gastrointestinal irritation.
While occasional grass eating followed by vomiting is usually harmless and considered a natural behavior, frequent or severe vomiting after eating grass could indicate underlying issues like gastrointestinal disorders, parasites, dietary deficiencies, or even toxin ingestion.
Common Reasons Why Dogs Eat Grass and Then Vomit
1. Upset Stomach or Nausea
One of the most well-known theories is that a dog eats grass and vomits as a natural way to relieve stomach discomfort.
This behavior is believed to help induce vomiting to expel whatever is causing the issue.
When dogs experience nausea from eating something they shouldn’t have (like spoiled food or garbage), they may instinctively try to eat grass. The blades of grass irritate their stomach lining, triggering vomiting.
In this case, the dog may seem desperate or frantic to find and consume grass.
Key signs your dog has an upset stomach:
Drooling
Licking lips frequently
Eating grass urgently
Vomiting bile or undigested food
Lethargy
If your dog is repeatedly eating grass and vomiting, especially yellow bile, it’s a good idea to consult a vet.
Related: Dog throwing up grass and bile (Here’s why)
2. Gastrointestinal Disorders
When dog vomiting after eating grass becomes a recurring pattern, it may indicate an underlying gastrointestinal issue.
Dogs suffering from gastritis, acid reflux, or inflammatory bowel disease (IBD) may eat grass in an attempt to soothe their digestive tract.
Gastrointestinal problems can also lead to:
Diarrhea
Frequent burping
Abdominal discomfort
Loss of appetite
Chronic dog eating grass and throwing up may be more than just a random habit—so keep an eye on frequency and duration.
3. Dietary Imbalance or Deficiency
In some cases, dogs may eat grass due to a nutritional deficiency, particularly fiber.
If your dog isn’t getting enough fiber in their diet, they might crave plant material to aid digestion.
Dogs are omnivores, and while commercial dog food provides essential nutrients, some dogs may still seek natural roughage like grass.
A fiber-deficient diet can cause irregular bowel movements and prompt dogs to eat grass as a form of self-medication.
Signs of dietary deficiency include:
Constipation or hard stools
Frequent grass eating without vomiting
Lackluster coat or poor body condition
If your dog consistently eats grass but doesn’t vomit afterward, consider discussing dietary adjustments with your vet.
Related: Dog eating grass and vomiting green stuff (Here’s why)
4. Boredom or Behavioral Habit
Sometimes, the reason behind dog eating grass and throwing up is behavioral rather than medical.
Dogs left alone in the yard or those lacking mental stimulation may chew on grass out of boredom.
This may also occur in dogs with compulsive chewing habits or anxiety-related behaviors.
Over time, it becomes a habit—even if it results in vomiting afterward.
Other behavioral signs:
Destructive chewing indoors
Digging or pacing
Barking excessively
Eating grass during walks or play
In such cases, increasing exercise, enrichment activities, and mental stimulation can reduce grass-eating behavior.
5. Parasites or Infections
Internal parasites like roundworms or hookworms can cause gastrointestinal discomfort, which may lead to dogs eating grass and vomiting as a side effect.
These parasites irritate the digestive tract and interfere with normal digestion.
Additionally, infections from bacteria or viruses can cause dogs to vomit after eating grass.
Look out for other symptoms:
Diarrhea with mucus or blood
Weight loss despite normal appetite
Scooting or excessive licking of the anus
Dull coat and lack of energy
Regular deworming and fecal exams are important in preventing parasite-related issues.
6. Toxin or Chemical Ingestion
If a dog has ingested a toxic substance—such as certain plants, pesticides, or human medications—they may eat grass and vomit as their body’s natural reaction to get rid of the toxin.
This is a serious concern. If your dog vomits after eating grass and shows additional symptoms like trembling, disorientation, or pale gums, seek emergency veterinary care.
Toxins that may lead to grass eating and vomiting:
Fertilizers or lawn chemicals
Chocolate or xylitol
Toxic plants (e.g., lilies, sago palm)
Spoiled food or garbage
In such scenarios, prompt action can save your dog’s life.
When to Be Concerned
Occasional grass eating is typically nothing to worry about. However, dog vomiting after eating grass becomes concerning when it’s:
Frequent (multiple times a week)
Accompanied by other symptoms like diarrhea, lethargy, or appetite loss
Involving blood in the vomit
Linked to potential toxin exposure
Here are clear signs that it’s time to visit the vet:
Persistent vomiting: More than once or twice a week.
Vomiting blood: Bright red or coffee ground-like vomit.
Lethargy or depression: Indicating systemic illness.
Dehydration signs: Dry gums, sunken eyes, or skin tenting.
Ongoing appetite loss: Refusing food for more than 24 hours.
Puppy or senior dog: More vulnerable to rapid health decline.
What to Do If Your Dog Eats Grass and Throws Up
If your dog has eaten grass and vomited but appears otherwise normal:
Withhold food for a few hours to rest the stomach.
Provide fresh, clean water in small amounts.
Gradually reintroduce a bland diet (like boiled chicken and rice).
Monitor for recurring symptoms or unusual behavior.
If vomiting continues or your dog appears unwell, seek veterinary advice immediately.
How to Prevent Dogs From Eating Grass
Here are practical tips to reduce the chances of your dog eating grass and vomiting:
Assess diet quality: Ensure your dog is on a complete and balanced diet with sufficient fiber.
Offer safe chew toys: Give alternatives to satisfy chewing urges.
Exercise and stimulation: Keep your dog active and mentally engaged.
Limit lawn access: Especially if chemicals or unknown plants are present.
Regular vet checkups: Stay ahead of parasites and digestive issues.
Key Takeaway
Dog eating grass and vomiting is a behavior that can stem from various causes—ranging from mild stomach upset to serious medical issues.
While occasional grass-eating is normal and not always harmful, frequent vomiting is a red flag that should not be ignored.
The most common causes include upset stomach, dietary deficiencies, gastrointestinal disorders, parasites, boredom, or exposure to toxins.
Understanding the context and accompanying symptoms can help determine the urgency of the situation.
If your dog is frequently eating grass and vomiting, consult with your veterinarian to rule out underlying conditions and find appropriate solutions.
With the right care, you can keep your furry friend happy, healthy, and grass-free.