If your dog is eating grass and having diarrhea at the same time, it may raise questions about their health, behavior, and diet.
This combination can be a sign of something minor or an indication of a more serious underlying condition.
We outline the reasons behind your dog eating grass and diarrhea, when you should be concerned, and what steps to take next.
Table of Contents
Dog Eating Grass and Diarrhea: Why It Happens
When a dog is eating grass and experiencing diarrhea, it often indicates that the dog’s digestive system is upset or irritated. Dogs may instinctively eat grass to soothe nausea, induce vomiting, or try to relieve discomfort caused by dietary indiscretion, parasites, infections, or stress.
Diarrhea alongside grass eating suggests that the digestive tract is inflamed or disturbed, possibly due to a sudden diet change, food intolerance, or ingestion of toxins.
Is It Normal for Dogs to Eat Grass?
Yes, dogs often eat grass for a variety of reasons, and in many cases, it is not cause for concern. Some of the reasons your dog might be eating grass include:
To induce vomiting: Some dogs eat grass to help themselves vomit if they are feeling nauseous.
Boredom or anxiety: Dogs may chew on grass as a way to cope with stress or because they lack stimulation.
Nutritional deficiencies: If your dog’s diet lacks certain nutrients or fiber, they might instinctively seek it from grass.
Natural instinct: Eating plant matter is an inherited behavior from wild canine ancestors.
However, if you notice dog eating grass and diarrhea occurring together frequently, it might indicate that grass consumption is a response to stomach discomfort or illness.
Dog Suddenly Eating Grass Like Crazy
A dog that suddenly starts eating grass excessively is often responding to nausea, stomach discomfort, or dietary imbalance.
It can also be triggered by boredom, stress, or habit, but a sudden change usually suggests an underlying physical cause.
Some dogs instinctively eat grass when their stomach feels unsettled. If the behavior is intense or new, especially when combined with vomiting, diarrhea, or reduced appetite, it may indicate gastrointestinal irritation that needs attention.
Reasons Behind Dog Eating Grass and Diarrhea
There are several potential reasons your dog might eat grass and have diarrhea simultaneously. Below are the most common causes:
1. Gastrointestinal Upset
One of the most frequent reasons for dog eating grass and diarrhea is mild gastrointestinal upset.
Dogs may instinctively consume grass to ease nausea or discomfort.
The grass may stimulate the stomach lining or encourage vomiting, which some dogs seek out when they feel ill.
However, if your dog eats grass and develops diarrhea or vomits frequently, this could be a sign of ongoing stomach irritation, and it’s best to consult your vet.
Related: Dog eating grass and coughing (Explained)
2. Dietary Indiscretion
Dogs are notorious for eating things they shouldn’t. Whether it’s garbage, spoiled food, or a dead animal, ingesting inappropriate substances can irritate the digestive tract.
This can lead to:
Vomiting
Diarrhea
Abdominal pain
Increased grass consumption
When the stomach is upset, your dog might eat grass in an effort to self-soothe or purge the contents of their stomach.
If the dog’s diarrhea persists more than 24 hours after eating grass or worsens, professional evaluation is needed.
3. Parasites and Worms
Intestinal parasites such as roundworms, hookworms, or giardia can cause a dog to experience diarrhea, along with other symptoms like weight loss and a dull coat.
These parasites can irritate the intestines and trigger a desire to eat non-food items like grass.
In some cases, dogs with worms may eat grass as an instinctive response to discomfort in their digestive system.
If your dog is eating grass and having diarrhea consistently, it’s worth checking for internal parasites through a vet-administered fecal test.
4. Sudden Diet Changes
Switching your dog’s food too quickly can lead to digestive issues.
Dogs may react to sudden dietary changes by developing diarrhea, vomiting, or bloating.
In turn, they may begin eating grass as a response to nausea or unease in their stomach.
To prevent dog diarrhea and grass eating caused by diet changes, always transition to a new food gradually over 7–10 days.
Start by mixing in small amounts of the new food and slowly increase it while reducing the old food.
5. Food Allergies or Intolerances
Food allergies and intolerances can lead to gastrointestinal inflammation, causing both diarrhea and nausea.
Dogs suffering from these conditions may eat grass to relieve discomfort.
Common culprits include:
Chicken
Beef
Dairy
Wheat
Soy
If your dog regularly has diarrhea and eats grass after meals, consider a hypoallergenic diet or an elimination trial under veterinary guidance.
6. Ingesting Toxins
If your dog has consumed a toxic substance—such as lawn chemicals, toxic plants, or spoiled food—it can cause immediate gastrointestinal symptoms.
Dogs may eat grass afterward, attempting to induce vomiting to remove the toxin.
Diarrhea caused by poisoning is typically severe and can be accompanied by:
Vomiting
Excessive drooling
Weakness
Collapse
If you suspect poisoning, contact your veterinarian or emergency animal clinic immediately.
7. Stress and Anxiety
Stress can trigger both behavioral and physical symptoms in dogs.
A stressed dog might eat grass compulsively and develop stress-induced diarrhea. Common stressors include:
Travel
Loud noises
Moving to a new home
Introduction of new pets or people
Dogs experiencing stress may also exhibit other symptoms such as pacing, panting, whining, or hiding.
If your dog is eating grass and has diarrhea during or after stressful events, anxiety could be the cause.
8. Underlying Illness
Persistent dog eating grass and diarrhea may be linked to more serious conditions like:
Inflammatory Bowel Disease (IBD)
Pancreatitis
Liver or kidney disease
Cancer of the gastrointestinal tract
These conditions often come with additional symptoms such as lethargy, weight loss, vomiting, or poor appetite.
If diarrhea continues for more than 48 hours or is accompanied by other concerning signs, seek immediate veterinary attention.
Related: Dog eating grass and being sick (Explained)
Dog Eating Grass and Has Diarrhea with Blood
If a dog eats grass and has diarrhea with blood, this is a serious warning sign. Blood in stool can result from intestinal inflammation, parasites, infections, poisoning, or gastrointestinal injury.
Grass eating may be the dog’s response to nausea or stomach pain, but it does not cause the bleeding itself.
This combination often suggests significant gut irritation and should be evaluated promptly, especially if the blood is frequent, dark, or accompanied by weakness.
Dog Eating Grass and Diarrhea and Vomiting
When a dog is eating grass, vomiting, and having diarrhea, it usually points to a moderate to severe digestive problem. Possible causes include infections, dietary indiscretion, parasites, pancreatitis, or toxin exposure.
Grass eating often occurs because the dog feels nauseous or has stomach discomfort.
The combination of vomiting and diarrhea increases the risk of dehydration quickly, and if symptoms continue or worsen, it indicates the digestive system is significantly affected.
Dog Eating Grass and Throwing Up Foam
When a dog eats grass and then throws up foam, it usually indicates nausea and stomach irritation. The foam is often a mixture of saliva and stomach acid, which appears when the stomach is empty or inflamed.
Grass eating may be the dog’s attempt to relieve discomfort or trigger vomiting.
Common causes include gastritis, dietary upset, parasites, or acid reflux. If this happens repeatedly, it suggests an ongoing digestive issue rather than a one-time reaction.
Puppy Eating Grass and Diarrhea
When a puppy eats grass and develops diarrhea, it often indicates digestive irritation or an upset stomach.
Common causes include dietary changes, parasites, viral or bacterial infections, or eating something inappropriate.
Puppies may eat grass because they feel nauseous or uncomfortable, and the same underlying issue may also be causing loose stool.
Because puppies are small and dehydrate quickly, this combination should be monitored closely even if the puppy still appears active.
What to Do If Your Dog Eats Grass and Has Diarrhea
For mild cases, home care focuses on soothing the digestive system and preventing dehydration. Here are a few immediate steps you can take:
1. Monitor Closely
Keep a close eye on your dog’s behavior, stool consistency, appetite, and water intake.
Note how often they eat grass and how frequently they experience diarrhea.
2. Provide Plenty of Fresh Water
Diarrhea can quickly dehydrate your dog, so always ensure access to clean, fresh water.
3. Offer a Bland Diet
Feed your dog a bland diet such as boiled chicken and white rice for 24–48 hours.
This can help soothe the digestive tract.
4. Avoid Further Grass Access
Limit your dog’s access to grassy areas temporarily to prevent excessive ingestion, especially if pesticides may be present.
5. Visit the Vet
If your dog’s symptoms persist or worsen, bring them to a veterinarian for evaluation.
Diagnostic tests like fecal exams, bloodwork, and imaging may be needed to determine the root cause.
Dog Eating Grass and Diarrhea: What to Watch For
While occasional grass consumption is usually harmless, you should be concerned if your dog shows any of the following signs:
Diarrhea lasting longer than 24–48 hours
Vomiting repeatedly after eating grass
Blood in stool or black, tar-like stool
Lethargy or collapse
Refusal to eat or drink
Significant weight loss
Signs of abdominal pain
These symptoms suggest something more serious than just a mild upset stomach and should be evaluated by a veterinarian.
Dog Eating Grass and Diarrhea: Treatment
Treatment depends on the underlying cause identified by a veterinarian. Your veterinarian may perform a physical exam and stool test to check for parasites, infections, or inflammation.
Treatment may include anti-diarrheal medication, deworming, antibiotics, or anti-nausea drugs if vomiting is also present.
Dietary changes to a bland or highly digestible food are often recommended. In more severe cases, fluids may be given to prevent dehydration. Once the underlying issue is treated, the grass-eating behavior usually reduces.
Prevention Tips
Feed a high-quality, balanced diet appropriate for your dog’s age and breed.
Avoid sudden food changes.
Keep lawns free of toxic plants and chemicals.
Schedule regular vet check-ups and parasite screenings.
Provide plenty of mental stimulation and physical exercise to reduce boredom-related grass eating.
Address anxiety with training, routines, and calming products if needed.
Key Takeaway
Dog eating grass and diarrhea can stem from simple causes like minor stomach upset or more complex health problems.
While occasional grass chewing isn’t usually serious, consistent grass-eating followed by diarrhea may signal an issue worth addressing.
If your dog shows signs of discomfort, persistent diarrhea, or other troubling symptoms, don’t wait—consult with your veterinarian. Immediate care can help identify the underlying cause and restore your dog’s digestive health, ensuring they return to their playful, tail-wagging self.