Dog Not Eating and Has Blood in Stool (Explained)

1. Gastrointestinal Infections

One of the most frequent causes of blood in a dog’s stool and lack of appetite is a GI infection, often bacterial, viral, or parasitic.

Infections cause inflammation in the intestines, which can lead to bleeding. The pain and discomfort caused by these infections also commonly reduce your dog’s appetite.

Symptoms may include:

• Diarrhea (possibly with mucus or blood)

• Vomiting

• Lethargy

• Fever

• Dehydration

Common culprits include Salmonella, E. coli, parvovirus, and giardia. Puppies are particularly susceptible to canine parvovirus, which can be fatal without prompt treatment.

2. Intestinal Parasites

Dogs that are not eating and have blood in their stool may be suffering from internal parasites like hookworms, whipworms, or roundworms. These parasites attach to the lining of the intestine and cause irritation or damage, leading to blood in the feces.

Signs of parasite infection:

• Visible worms or eggs in stool

• Weight loss despite eating (if appetite isn’t fully lost)

• Scooting or licking the anus

• Bloating or abdominal discomfort

Regular deworming and fecal exams are critical to preventing these infestations.

3. Dietary Indiscretion or Sudden Diet Change

Dogs are notorious for eating things they shouldn’t—spoiled food, garbage, bones, or fatty table scraps.

This is known as dietary indiscretion and can cause GI upset, resulting in bloody stools and refusal to eat.

Alternatively, a sudden change in dog food can also trigger these symptoms due to the digestive system struggling to adjust.

Symptoms of dietary upset include:

• Vomiting

• Diarrhea (with or without blood)

• Loss of appetite

• Bloating

Always transition to new food gradually over 7–10 days to avoid digestive issues.

Related: Dog not eating and vomiting (Explained)

4. Inflammatory Bowel Disease (IBD)

IBD in dogs is a chronic condition in which the digestive tract becomes persistently inflamed.

The inflammation interferes with normal digestion and nutrient absorption, which can lead to blood in the stool and poor appetite.

Other IBD signs:

• Weight loss

• Chronic diarrhea or soft stools

• Vomiting

• Gas and bloating

IBD is often diagnosed through a combination of blood work, ultrasound, and biopsies, and treatment may involve prescription diets and medications.

5. Stress or Anxiety

Yes—stress in dogs can impact digestion. Dogs that are anxious or stressed may stop eating and experience stress colitis, a condition where inflammation of the colon leads to bloody stools.

Stress triggers can include:

• Travel or boarding

• Loud noises (thunderstorms, fireworks)

• New household members or pets

• Separation anxiety

Symptoms of stress-related digestive issues:

• Soft or bloody stool

• Appetite changes

• Hiding or pacing

• Whining or panting

Reducing stress and using calming aids (natural or prescribed) can help relieve symptoms.

6. Foreign Object Ingestion

If your dog swallows something indigestible—like a sock, toy, or piece of bone—it can irritate or obstruct the digestive tract.

This often causes bloody stools and loss of appetite due to pain or blockage.

Warning signs of a blockage:

• Straining to defecate

• Vomiting

• Bloating

• Weakness

• Restlessness or signs of pain

This is a medical emergency that may require surgery. Never wait too long if you suspect your dog has swallowed a foreign object.

Related: Dog not eating and sleeping alot (Explained)

7. Poisoning or Toxin Exposure

Dogs exposed to toxic substances like rodenticides, certain plants, or household cleaners may experience internal bleeding, resulting in blood in the stool.

Ingestion of toxins can also lead to nausea, vomiting, and appetite loss.

Some toxic foods or substances include:

• Chocolate

• Grapes and raisins

• Xylitol (sugar substitute)

• Human medications

• Antifreeze

If you suspect poisoning, contact your vet or an emergency clinic immediately.

8. Cancer or Polyps

Though more common in older dogs, tumors in the GI tract can cause symptoms such as weight loss, lack of appetite, and bloody stool in dogs. Polyps or cancerous growths may bleed, especially as they grow or ulcerate.

These conditions often require:

• Diagnostic imaging (X-rays, ultrasound)

• Endoscopy or biopsy

• Surgical removal

• Chemotherapy (in some cases)

When to Worry About a Dog Not Eating and Blood in Stool

If your dog shows these two symptoms together, it’s important not to wait too long before seeking veterinary help. Even if the symptoms seem mild, they may point to an underlying condition that requires treatment.

Seek immediate veterinary care if your dog:

• Refuses food for more than 24 hours

• Passes large amounts of blood in stool or has black, tarry feces

• Is also vomiting, especially with blood

• Becomes lethargic or collapses

• Shows signs of pain or bloating

• Is a puppy, senior, or has a chronic condition (they are more vulnerable)

Diagnosis and Treatment

A veterinarian will typically run a series of tests to diagnose the problem:

• Fecal exam (to check for parasites or bacteria)

• Blood work (to assess organ function and detect infections)

• X-rays or ultrasound (to rule out blockages or tumors)

• Endoscopy or biopsy (for chronic conditions like IBD)

Treatment varies depending on the cause, but may include:

• Fluid therapy for dehydration

• Anti-parasitic or antibiotic medications

• Prescription diets

• Pain or anti-inflammatory medication

• Surgery (in severe cases like foreign object removal or tumors)

How to Prevent Dog Not Eating and Blood in Stool

While some causes are unavoidable, many can be prevented with good care:

• Keep harmful substances out of reach

• Deworm regularly and test feces annually

• Feed a consistent, high-quality diet

• Avoid sudden dietary changes

• Reduce stress and provide a calm environment

• Schedule regular vet checkups

Key Takeaway: Dog Not Eating and Has Blood in Stool

If your dog is not eating and has blood in their stool, it’s a clear sign something is wrong.

While occasional appetite dips or minor stool changes can be normal, the combination of anorexia and bloody stool in dogs warrants prompt attention.

Early detection and treatment are essential to helping your dog recover. Whether the cause is infection, stress, parasites, or something more serious like cancer, a vet visit is the safest course of action.

By staying alert to these symptoms and acting quickly, you can ensure your dog gets the care they need to return to their happy, healthy self.