Dog Pooping Blood? Causes, Emergency Signs & When to See a Vet

Seeing blood in your dog's stool is alarming. Sometimes it's a minor issue that resolves on its own. Other times it's a life-threatening emergency. Here is how to tell the difference.

Two Types of Blood in Stool

Hematochezia (Bright Red Blood)

Fresh, bright red blood in or on the stool. Means the bleeding is coming from the lower GI tract — the colon, rectum, or anus. Common causes: stress colitis, parasites (whipworms, hookworms), dietary indiscretion, anal gland issues, rectal polyps or tumors.

Melena (Dark, Tarry Blood)

Black, tarry stool that looks like coffee grounds. Means the blood has been digested — bleeding is from the upper GI tract (stomach or small intestine). This is more serious. Common causes: stomach ulcers, NSAID toxicity, rat poison ingestion, cancer, severe pancreatitis.

Common Causes by Severity

Usually Minor (Schedule Vet Visit)

Stress colitis: Bright red blood + mucus, often after boarding, travel, or routine change. Dog is otherwise energetic. Dietary indiscretion: Dog ate something weird, mild bloody stool, resolves in 24-48 hours with bland diet. Anal gland issues: Blood on the surface of formed stool, dog scooting.

Potentially Serious (Urgent Vet Visit)

Parasites: Hookworms and whipworms cause chronic bloody diarrhea. Needs deworming. Inflammatory Bowel Disease: Chronic intermittent bloody stool, weight loss, vomiting. Colitis: Inflammation of the colon, bright red blood + mucus + urgency.

Life-Threatening (EMERGENCY — Go NOW)

Parvovirus: Bloody diarrhea + vomiting + extreme lethargy in an unvaccinated puppy. Fatal within 48 hours. Hemorrhagic Gastroenteritis: Sudden onset of profuse bloody diarrhea ("raspberry jam"), rapid dehydration, shock. Rat poison: Anticoagulant rodenticide causes internal bleeding. Gums may be pale, dog weak. Intestinal obstruction: Vomiting + bloody stool + abdominal pain.

What to Do

If the dog is energetic with a small amount of bright red blood: monitor and feed a bland diet. If the dog is lethargic, vomiting, has dark/tarry stool, or has heavy bleeding: EMERGENCY VET NOW. Bring a stool sample and take a photo to show your vet.

Never give human anti-diarrhea medications like Pepto-Bismol or Imodium without veterinary approval.