Dog Bloody Diarrhea and Not Eating: What It Means

Dog Bloody Diarrhea and Not Eating: Common Causes 

1. Gastrointestinal infections

Bacterial, viral, or parasitic infections are among the top reasons dogs experience bloody diarrhea and stop eating.

Organisms such as Salmonella, E. coli, Parvovirus, Giardia, and roundworms can inflame the intestines, damage the GI lining, and cause blood in the stool.

Dogs with gastrointestinal infections may refuse to eat because of abdominal pain, cramping, or nausea.

The severity of symptoms can vary based on the type of pathogen, the dog’s age, and their immune health.

Signs to look for:

• Bloody or mucous-filled diarrhea

• Vomiting

• Fever

• Lethargy

• Dehydration

Puppies, in particular, are highly susceptible to infections like Parvovirus, which can be fatal without prompt veterinary care.

Related: Dog diarrhea and not eating (Causes and when to worry) 

2. Dietary indiscretion

Dogs are curious and often eat things they shouldn’t.

Consuming garbage, spoiled food, bones, or toxic substances can irritate the intestines or cause blockages, leading to dog bloody diarrhea and not eating.

This “dietary indiscretion” often results in a condition called hemorrhagic gastroenteritis (HGE), which is marked by sudden, severe bloody diarrhea and vomiting.

The exact cause of HGE is unknown, but it is thought to be related to stress, bacterial toxins, or food sensitivities.

Other signs may include:

• Vomiting

• Abdominal pain

• Sudden onset of bloody diarrhea

• Collapse or weakness in severe cases

HGE is potentially life-threatening and requires urgent treatment to prevent dehydration and shock.

3. Inflammatory bowel disease (IBD)

IBD is a chronic condition where the intestinal walls become inflamed and thickened.

This disrupts digestion and nutrient absorption, leading to dog bloody diarrhea and not eating.

Dogs with IBD may have intermittent episodes of diarrhea, vomiting, weight loss, and appetite loss.

The exact cause isn’t always clear, but it could be linked to immune system dysfunction, genetics, food intolerance, or gut microbiome imbalance.

Watch for:

• Chronic diarrhea (sometimes with blood or mucus)

• Poor appetite

• Weight loss

• Bloating or discomfort

Managing IBD typically involves a combination of dietary changes, probiotics, and medications like corticosteroids.

4. Parasites

Intestinal parasites like hookworms, whipworms, coccidia, and Giardia can damage the intestinal lining and cause dog bloody diarrhea and not eating.

These parasites feed off your dog’s blood or intestinal content, leading to anemia, malnutrition, and GI upset.

Dogs with parasite infections may exhibit:

• Bloody, soft, or watery stools

• Weight loss

• Vomiting

• Poor coat condition

• Potbellied appearance in puppies

Routine fecal exams and deworming are essential to detect and treat parasitic infestations.

Related: Dog diarrhea and shaking (Here’s why)

5. Toxins or poisoning

Ingesting toxic substances such as chocolate, xylitol, household cleaners, medications, rat poison, or certain plants can lead to bloody diarrhea and a sudden loss of appetite.

Toxins damage the GI lining or internal organs, leading to internal bleeding, vomiting, and systemic symptoms.

Telltale signs include:

• Bright red blood in diarrhea

• Excessive drooling or panting

• Seizures

• Vomiting

• Weakness or collapse

If you suspect your dog may have ingested a toxin, contact a vet or poison control immediately. Delayed treatment can be fatal.

6. Stress or anxiety

Stress can upset your dog’s digestive system, leading to colitis (inflammation of the colon), which often results in bloody diarrhea.

Stressful triggers can include boarding, moving to a new home, loud noises, or changes in the household.

In addition to dog bloody diarrhea and not eating, stress-related colitis may involve:

• Frequent urge to defecate

• Straining

• Small amounts of blood or mucus in stool

• Behavioral changes (hiding, pacing, whimpering)

While stress-induced GI issues can improve with calm environments and dietary support, persistent symptoms require evaluation.

7. Cancer

Unfortunately, cancers such as intestinal lymphoma or adenocarcinoma can also lead to bloody diarrhea and appetite loss in dogs.

Tumors in the GI tract interfere with digestion, often causing chronic symptoms.

Possible indicators:

• Persistent or recurrent bloody diarrhea

• Weight loss

• Vomiting

• Fatigue

• Swollen abdomen

A veterinary diagnosis is essential through imaging, biopsy, and bloodwork.

8. Medication side effects

Certain medications, especially NSAIDs (non-steroidal anti-inflammatory drugs), corticosteroids, or antibiotics, can irritate your dog’s digestive tract, leading to symptoms like bloody diarrhea and not eating.

If your dog recently started a new medication, speak with your vet about possible side effects or alternatives.

What to do if your dog has bloody diarrhea and is not eating

If your dog is experiencing bloody diarrhea and not eating, prompt action is critical.

This is not a condition to monitor at home for long periods, especially if other symptoms are present.

Here are the steps to follow:

1. Contact your veterinarian immediately.
   Bloody diarrhea is a medical emergency in many cases. Don’t delay care, especially if your dog is very young, elderly, or showing additional signs of illness like vomiting, fever, or collapse.

2. Withhold food for 12–24 hours (only if advised by your vet).
   In mild cases, vets may recommend temporarily withholding food to allow the GI tract to rest. However, this is not advisable for puppies or if there’s significant blood loss or dehydration.

3. Keep your dog hydrated.
   Diarrhea leads to fluid loss. Offer clean water and consider oral rehydration solutions if approved by your vet. If your dog refuses to drink or is vomiting, they may need IV fluids.

4. Bring a stool sample.
   Your vet may want to analyze your dog’s stool to check for parasites, bacteria, or signs of internal bleeding. Collect a fresh sample if possible.

5. Prepare for diagnostic tests.
   Depending on your dog’s symptoms, your vet might perform blood tests, X-rays, ultrasound, or endoscopy to determine the cause.

6. Follow treatment plans closely.
   Treatments may include:

   • Deworming medication

   • Antibiotics or antivirals

   • Anti-inflammatory drugs

   • GI-protective medications

   • Prescription diets

   • Probiotics or prebiotics

7. Avoid giving human medications.
   Never administer over-the-counter medications like Pepto-Bismol, aspirin, or Imodium to your dog without veterinary approval. These can worsen the condition or cause toxicity.

When to seek emergency veterinary care

You should go to the vet immediately if:

• The diarrhea is profuse or jet-like

• You see dark, tarry stools (indicating internal bleeding)

• Your dog vomits repeatedly or cannot keep water down

• There is lethargy, shaking, or collapse

• Your dog’s gums are pale or gray (possible shock)

• There is no improvement within 24 hours

Key Takeaway

When your dog has bloody diarrhea and is not eating, it often signals a deeper health issue that needs immediate attention.

Whether caused by infection, parasites, stress, toxins, or chronic illness, the combination of these symptoms requires a thorough veterinary exam.

While mild cases may resolve with treatment and dietary care, more serious causes can rapidly worsen without intervention. Always err on the side of caution.

Early diagnosis and proper treatment can make all the difference in your dog’s recovery and well-being.