If your dog is eating grass and not eating their food while also experiencing diarrhea, it could indicate a range of health or behavioral issues that need your attention.
While dogs occasionally nibble on grass and skip meals without cause for concern, the combination of grass eating, loss of appetite, and diarrhea may signal something more serious.
We outline the common reasons behind this behavior can help you take the right steps to support your pet’s health and comfort.
Dog Eating Grass and Not Eating and Diarrhea: Why It Happens
When a dog is eating grass and not eating and diarrhea is present, it’s often a sign of gastrointestinal distress or an underlying health issue.
This behavior can be triggered by dietary indiscretion, parasites or gastrointestinal infections, nutritional deficiencies, stress or anxiety, inflammatory bowel disease or food intolerance, poisoning or toxin ingestion, and pancreatitis.
While grass eating may be instinctive, its combination with appetite loss and diarrhea points to a potential problem that should not be ignored, especially if symptoms persist or worsen.
Dog Eating Grass and Not Eating and Diarrhea: Common Causes
Dietary indiscretion or stomach upset
One of the most common causes of a dog eating grass and not eating and diarrhea is dietary indiscretion.
Dogs are naturally curious and sometimes eat things they shouldn’t—whether it’s table scraps, spoiled food, or something they’ve found outside.
When this happens, the dog’s gastrointestinal system can become irritated, leading to vomiting or diarrhea.
Eating grass may be the dog’s attempt to induce vomiting or soothe an upset stomach.
At the same time, the discomfort may cause your dog to refuse food altogether.
If your dog is refusing food but consuming grass and having loose stools, this may point to stomach upset due to something they’ve eaten that didn’t agree with them.
Related: Dog eating grass and not eating (Here’s why)
Parasites or gastrointestinal infections
Intestinal parasites such as hookworms, roundworms, or giardia can cause symptoms like diarrhea, poor appetite, and a desire to eat grass.
Similarly, viral or bacterial infections of the gastrointestinal tract can cause inflammation that leads to diarrhea and nausea, which may trigger a dog to avoid food while seeking out grass.
In these cases, the dog’s instinct may drive them to consume grass to try to relieve discomfort or encourage vomiting.
Dogs with parasitic infections often have foul-smelling stool, bloating, and lethargy in addition to diarrhea and appetite changes.
Nutritional deficiency
A nutritional imbalance or deficiency may also cause a dog to exhibit unusual eating behaviors, such as consuming grass.
If your dog isn’t getting the right nutrients, they might start eating grass in an attempt to make up for what’s missing, especially fiber or certain minerals.
This imbalance can lead to gastrointestinal issues, contributing to diarrhea and a decreased appetite.
If your dog is eating grass and not eating food consistently, their current diet may not be meeting their needs.
Related: Dog Eating Grass and Not Eating and Vomiting (Explained)
Stress or anxiety
Stress can manifest in dogs in a variety of ways, including behavioral changes like refusing food, eating grass compulsively, and experiencing diarrhea.
Dogs are creatures of habit, and sudden changes in their environment—such as moving homes, a new pet, or loud noises—can cause anxiety that leads to digestive disturbances.
Dogs under stress may also experience nausea, causing them to reject food.
Diarrhea caused by stress is common, particularly in sensitive or high-strung breeds.
The act of eating grass can be a self-soothing behavior for some anxious dogs.
Inflammatory bowel disease (IBD) or food intolerance
Inflammatory bowel disease and food intolerances can cause chronic diarrhea, poor appetite, and a tendency to eat non-food items like grass.
IBD is a chronic condition that affects the intestines and may cause ongoing gastrointestinal symptoms.
Dogs with IBD often experience abdominal discomfort, leading them to avoid food and seek relief by eating grass.
Similarly, food intolerances can cause ongoing irritation of the digestive tract, resulting in diarrhea and nausea.
If your dog has been eating grass and not eating for an extended period alongside diarrhea, and if this pattern repeats, it may be time to consider an underlying chronic issue.
Related: Dog eating grass and not throwing up (Explained)
Poisoning or toxin ingestion
Another serious reason for a dog eating grass and not eating and diarrhea could be poisoning.
Dogs may ingest toxins accidentally—from lawn chemicals, certain plants, spoiled food, or human medications.
These substances can cause immediate gastrointestinal distress.
Diarrhea and vomiting are common symptoms of poisoning, and a dog may instinctively eat grass to induce vomiting or relieve nausea.
A loss of appetite can also occur if the toxin affects the stomach, liver, or other internal organs.
If your dog suddenly starts eating grass obsessively, refuses food, and has diarrhea, this could be an emergency situation.
Pancreatitis
Pancreatitis is a painful and potentially serious condition in which the pancreas becomes inflamed.
It can be triggered by eating fatty foods, certain medications, or underlying diseases.
Symptoms of pancreatitis include diarrhea, vomiting, lethargy, refusal to eat, and sometimes eating grass.
Dogs with pancreatitis may try to relieve their discomfort by consuming grass.
If untreated, pancreatitis can become life-threatening, so it’s critical to seek veterinary attention if these symptoms are present.
What to do if your dog is eating grass and not eating and has diarrhea
If your dog is eating grass and not eating and diarrhea is present, your response should depend on the severity and duration of the symptoms.
Here’s a guide to help you determine what steps to take:
1. Monitor closely for 24–48 hours:
If your dog is still active, drinking water, and only mildly affected, you can monitor them for a day or two.
During this time, offer bland food such as boiled chicken and rice, and withhold treats or anything new.
Make sure they have access to clean, fresh water to stay hydrated.
2. Prevent access to harmful substances:
Check your yard and home for any potential toxins—such as pesticides, harmful plants, or trash—that your dog may have ingested.
Prevent future access to these areas to avoid further gastrointestinal upset.
3. Avoid giving human medications:
Do not give your dog over-the-counter human medications to stop diarrhea, as many are toxic to dogs and can make the condition worse.
4. Watch for signs of dehydration:
Diarrhea can quickly lead to dehydration.
Look for dry gums, sunken eyes, weakness, and excessive panting.
Dehydration is serious and warrants prompt veterinary care.
5. Consult a veterinarian if symptoms persist or worsen:
If your dog continues eating grass, refuses food, and has diarrhea for more than 48 hours, or if the diarrhea becomes severe or bloody, see your vet immediately.
Puppies, older dogs, and dogs with chronic conditions are particularly vulnerable to complications and should not wait.
6. Bring a stool sample to the vet:
If you do visit the vet, bring a fresh stool sample.
This can help identify the presence of parasites, bacteria, or other abnormalities and make diagnosis faster and more accurate.
7. Consider a diet review:
If these symptoms are recurring, your dog may have a food intolerance or nutritional imbalance.
Your vet may recommend an elimination diet, blood tests, or switching to a prescription diet tailored to your dog’s needs.
Key Takeaway
When a dog is eating grass and not eating and diarrhea occurs at the same time, it’s usually a sign that something is not quite right.
While grass eating alone isn’t always concerning, the combination of symptoms—especially loss of appetite and diarrhea—points to a need for further investigation.
From mild dietary upsets to serious medical issues like poisoning, parasitic infections, or chronic conditions, these symptoms shouldn’t be ignored.
As a pet owner, your attentiveness and prompt action can make all the difference in your dog’s recovery.
Always err on the side of caution: if you’re unsure whether it’s serious, consult your vet.
With the right care, most cases can be treated successfully, and your dog can return to their playful, tail-wagging self in no time.