Finding blood in your dog’s stool is distressing enough—but when your dog also stops eating, it becomes a serious concern.
We cover why your dog might have blood in the stool and not be eating, what underlying issues could be causing it, and what steps you should take to keep your pup safe and on the road to recovery.
Dog Blood in Stool and Not Eating: Why It Happens
A dog with blood in stool and not eating may be experiencing gastrointestinal infections, parasites, dietary indiscretion, stress colitis, food intolerance, pancreatitis, inflammatory bowel disease, toxin exposure, or even tumors.
These conditions cause inflammation, damage, or bleeding in the GI tract—often accompanied by nausea or pain that reduces appetite.
Dog Blood in Stool and Not Eating: Common Causes
1. Gastrointestinal Infections
Bacterial or viral infections in the digestive tract are a leading cause of blood in the stool, especially in dogs who’ve recently visited the park, kennel, or daycare. Common culprits include Clostridium, Salmonella, E. coli, or viral agents like parvovirus (especially in puppies).
These infections can damage the gut lining, leading to:
Bright red blood in stool (hematochezia)
Diarrhea with mucus or foul odor
Vomiting
Lethargy and disinterest in food
Parvovirus, in particular, is life-threatening and requires immediate treatment. If your dog is very young, unvaccinated, and showing blood in stool with vomiting and appetite loss, act urgently.
Related: Dog vomiting and not eating (Causes and when to worry)
2. Parasites
Intestinal parasites like hookworms, whipworms, and giardia irritate the intestinal walls, which can lead to bloody or mucous-streaked stools. In moderate to heavy infestations, appetite loss follows due to abdominal discomfort or malnutrition.
Signs of parasitic infection may include:
Soft, greasy, or dark stools
Scooting or excessive licking around the rear
Visible worms or rice-like segments in stool
Weight loss or bloating
Puppies, rescue dogs, or those not on regular deworming protocols are especially at risk. Many parasites are zoonotic (can spread to humans), so don’t delay treatment.
3. Dietary Indiscretion or Sudden Food Changes
Dogs love to sniff, lick, and chew things they shouldn’t—and sometimes that curiosity leads to bloody stool and stomach upset. Eating spoiled food, garbage, bones, fatty table scraps, or non-food items can inflame or even tear parts of the GI tract.
These incidents often cause:
Sudden diarrhea or loose stool with blood
Vomiting and nausea
Gurgling sounds from the belly
A noticeable loss of appetite
Even a simple change in food (especially without a slow transition) can disrupt gut flora and trigger inflammation or bleeding in sensitive dogs.
4. Food Intolerance or Allergy
Some dogs develop sensitivity to ingredients like chicken, beef, wheat, or dairy. These dogs may experience colitis, where the large intestine becomes inflamed, causing bright red blood and mucus in the stool.
Other symptoms can include:
Intermittent diarrhea or soft stools
Gas and bloating
Reluctance to eat or fussiness with food
Skin itching or chronic ear infections (in allergy cases)
Left unchecked, long-term exposure to intolerant foods can damage the gut lining and worsen digestion, eventually leading to full food refusal.
5. Stress Colitis
Dogs under stress—such as moving to a new home, staying in a kennel, or being separated from their owner—may develop stress-induced colitis. This is a form of large intestine inflammation where blood and mucus often appear in loose stools.
It’s especially common in:
Young, anxious, or high-strung dogs
Dogs with a sudden routine change
Shelter or adopted dogs within the first few weeks
Affected dogs may seem otherwise normal but refuse food or become slightly lethargic due to gut discomfort or emotional overwhelm.
6. Pancreatitis
Pancreatitis (inflammation of the pancreas) can sometimes cause bloody diarrhea in dogs, especially if the pancreas affects surrounding digestive organs. Often caused by fatty meals or underlying conditions like hypothyroidism, it can be extremely painful.
Symptoms include:
Vomiting and diarrhea (with or without blood)
Hunched posture or abdomen sensitivity
Severe loss of appetite
Lethargy or collapse
Pancreatitis always warrants veterinary care and often requires hospitalization and IV fluids.
7. Inflammatory Bowel Disease (IBD)
Dogs with chronic inflammation of the GI tract may develop IBD, which damages the lining of the intestines. This leads to poor absorption of nutrients, intermittent vomiting, and bloody or mucousy diarrhea.
Other signs include:
Long-term weight loss
Reluctance to eat despite hunger
Episodes of abdominal discomfort
Poor coat condition
IBD can often be managed with special diets, medications, and gut-friendly supplements—but early diagnosis is key.
8. Toxin Ingestion
If your dog has ingested something toxic—like rodenticides, certain human medications, or chemicals—bloody stool and vomiting may follow. Toxins can cause internal bleeding, stomach lining damage, or systemic illness.
Symptoms to watch for:
Pale gums
Excessive drooling
Unsteady walking or collapse
Refusal to eat
This is a veterinary emergency. Bring a sample of what they may have ingested and seek help immediately.
What to Do If Your Dog Has Blood in Stool and Isn’t Eating
If your dog is otherwise stable but showing these symptoms:
Withhold food for 8–12 hours, then try small amounts of bland food like boiled chicken and rice
Ensure they have access to clean water, and encourage small sips to prevent dehydration
Collect a stool sample for your vet, noting any mucus, consistency, or color
Avoid giving treats, table food, or new diets while symptoms are present
Monitor for signs of worsening, such as increased lethargy or repeated vomiting
If you notice black, tarry stool (melena), which indicates digested blood, go to the vet immediately—this can mean internal bleeding in the upper GI tract.
When to Call or Visit Your Vet
See your vet as soon as possible if:
Your dog hasn’t eaten in more than 24 hours
Blood in the stool is bright red or persistent
Diarrhea is frequent, severe, or foul-smelling
Your dog is vomiting, lethargic, or has a fever
They’re very young, very old, or immunocompromised
Your vet may recommend fecal testing, bloodwork, imaging, or even endoscopy, depending on severity and history.
Key Takeaway
If your dog has blood in their stool and is not eating, it’s more than a stomach bug—it could be a sign of inflammation, infection, or something more serious.
Whether it’s parasites, pancreatitis, or a reaction to something they ate, the combination of these symptoms always warrants attention.
Trust your instincts. If your dog doesn’t seem themselves, call your vet.
Fast action can not only bring your pup relief—it could save their life.