When your dog is vomiting, not eating, and passing blood in their stool, it’s time to be seriously concerned.
While any one of these symptoms on its own is troubling, the combination can point to a potentially life-threatening illness.
We outline why this happens, what to do, and when to seek veterinary care.
Dog Vomiting Not Eating and Blood in Stool: Why It Happens
A dog that is vomiting, not eating, and passing blood in their stool is often linked to gastrointestinal infections, hemorrhagic gastroenteritis (HGE), toxin ingestion, ulcers, or parvovirus.
Vomiting and appetite loss are your dog’s way of reacting to internal distress, while blood in the stool indicates inflammation or bleeding in the digestive tract.
Whether the blood in the stool is bright red or dark and tarry, it’s a clear sign that your dog needs immediate veterinary attention.
Dog Vomiting, Not Eating, and Blood in Stool: Common Causes
1. Hemorrhagic Gastroenteritis (HGE)
HGE is a sudden, acute condition that causes explosive vomiting, bloody or jelly-like diarrhea, loss of appetite, and lethargy.
The cause is often unknown but may be linked to stress, bacteria, or food intolerance.
HGE can cause severe dehydration and rapid decline, especially in small or toy breed dogs.
Treatment includes aggressive IV fluids, anti-nausea medication, and supportive care. Early intervention is key to survival.
2. Parvovirus
Parvovirus is a contagious viral infection, especially dangerous for puppies and unvaccinated dogs.
It causes violent vomiting, bloody diarrhea, extreme lethargy, and complete loss of appetite.
If your dog is showing these signs, particularly with bloody stool and vomiting, it is a medical emergency.
Immediate hospitalization with intensive care is often required for recovery.
Related: Dog vomiting and not eating (Causes and when to worry)
3. Gastrointestinal Ulcers
Stomach or intestinal ulcers can lead to vomiting (sometimes with blood), black or tarry stools, inappetence, and fatigue.
These ulcers may develop from long-term use of NSAIDs, stress, or underlying illness.
Ulcers can perforate and lead to internal bleeding or infection.
Your vet can confirm the diagnosis through imaging and prescribe medications to heal the ulcers and protect the GI lining.
4. Toxin Ingestion
Some toxins—especially rodent poisons and human medications—cause internal bleeding, bloody stool, vomiting, and appetite loss.
Even small doses can be fatal depending on the toxin type and your dog’s size.
Call your vet or a pet poison hotline immediately if you suspect toxin exposure.
Vomiting with blood or bloody stool after potential poisoning is an emergency.
Related: Dog vomiting not eating not pooping (What it means)
5. Intestinal Parasites or Bacterial Infection
Parasites like hookworms or infections from bacteria such as Salmonella or Clostridium can cause vomiting, loss of appetite, and bloody stool—especially in puppies or dogs with weakened immune systems.
Stool samples can reveal the cause, and treatment often involves dewormers, antibiotics, and a temporary bland diet to help the gut heal.
What to Do If Your Dog Is Vomiting, Not Eating, and Passing Blood in Stool
While it’s natural to want to help at home, this combination of symptoms requires a vet visit. That said, while waiting for your appointment or in mild cases, here’s what you can do:
Withhold food for 8–12 hours, but continue offering small amounts of water or ice chips.
Do not give over-the-counter medications, especially anti-diarrheals or human painkillers.
Note the color and consistency of the stool—bright red blood vs. black stool gives clues about bleeding location.
Keep your dog calm and warm, especially if they’re weak or trembling.
Take photos or bring a stool sample to your vet for easier diagnosis.
If your dog is lethargic, vomiting frequently, or passing large amounts of blood, go to an emergency vet clinic immediately.
When to Call or Visit Your Vet
These symptoms warrant an urgent veterinary exam if:
Your dog is vomiting and has bright red blood or black stool
They haven’t eaten in over 24 hours
Your dog is weak, unresponsive, or showing signs of dehydration
The vomiting is persistent or projectile
You suspect they ingested poison, bones, or spoiled food
Your dog is a puppy, senior, or immunocompromised
Diagnostic tools like blood work, stool testing, and imaging help determine the cause and guide treatment.
Read more: Dog Vomiting and Not Eating but Drinking Water (What it means)
Key Takeaway
Vomiting, not eating, and blood in your dog’s stool is a red flag you should never ignore.
These symptoms often point to serious underlying issues like infections, toxins, or internal bleeding that require immediate medical attention.
Acting quickly can give your dog the best chance at a full recovery.
As frightening as these signs are, being informed—and calling your vet right away—can save your dog’s life.