When you notice your dog having loose stool mixed with blood, it’s completely understandable to feel alarmed. Bloody diarrhea (loose stool) can range from a minor irritation to a sign of a serious health issue requiring urgent care.
The key is identifying whether it’s a one-time occurrence or part of a pattern — and knowing when to seek veterinary help.
Understanding the possible causes can help you take the right next steps for your dog’s health.
We outline the common reasons behind loose stool with blood in dogs, what you can do at home, and when to seek veterinary help to ensure your dog receives the right care.
Dog Loose Stool and Blood: Why It Happens
A dog with loose stool and blood is often a sign of irritation or inflammation within the digestive tract. While it may result from something minor, such as a sudden diet change or stress, it can also indicate more serious issues like infections, parasites, or gastrointestinal disease.
Dog Loose Stool and Blood: Common Causes
Dietary Indiscretion or Sudden Food Change
One of the most frequent causes of loose, sometimes bloody stool is what vets call “dietary indiscretion.” Dogs often eat things they shouldn’t — such as garbage, spoiled food, or unfamiliar treats.
This sudden change can irritate the gastrointestinal tract, leading to inflammation and bleeding.
Even a sudden switch in dog food brands or treats can upset your dog’s sensitive stomach.
The irritation may cause mild bleeding from the intestinal lining, resulting in streaks or spots of blood in loose stool.
Read more: Dog Loose Stool with No Other Symptoms (What it means)
Parasites and Worms
Intestinal parasites like hookworms, whipworms, and roundworms can damage the intestinal walls, leading to both diarrhea and blood in the stool.
Puppies are especially vulnerable, but adult dogs can also get infected from contaminated soil, feces, or fleas.
If your dog’s stool looks tarry, dark, or has bright red streaks, it’s crucial to have a fecal test done by your vet. Regular deworming and maintaining good hygiene help prevent reinfection and protect your pet’s digestive health.
Bacterial or Viral Infections
Infections caused by bacteria such as Salmonella, E. coli, or Clostridium perfringens, or viruses like parvovirus, can lead to severe bloody diarrhea.
Parvovirus, in particular, is a life-threatening condition that often begins with vomiting, lethargy, and foul-smelling bloody stool.
Puppies or unvaccinated dogs are most at risk. If you notice rapid deterioration or persistent bloody diarrhea, seek immediate veterinary attention — early treatment can be life-saving.
Inflammatory Bowel Disease (IBD)
Chronic loose stool with intermittent bleeding can sometimes be a sign of Inflammatory Bowel Disease (IBD).
This long-term condition causes ongoing inflammation in the intestines and may lead to poor nutrient absorption, weight loss, and recurring episodes of bloody diarrhea.
IBD can be triggered by immune dysfunction, food sensitivities, or bacterial imbalance. Your vet may recommend special diets, anti-inflammatory medication, or probiotics to help manage the symptoms and restore digestive balance.
Hemorrhagic Gastroenteritis (HGE)
If your dog suddenly develops profuse, watery, bloody diarrhea, Hemorrhagic Gastroenteritis (HGE) may be the cause.
This condition often strikes without warning and can quickly lead to severe dehydration and shock.
The exact cause isn’t always clear, but stress, diet changes, or bacterial toxins may play a role. HGE is an emergency — prompt veterinary care with fluid therapy and medication is essential for recovery.
Food Sensitivities
Some dogs react negatively to certain ingredients in their diet, such as beef, chicken, dairy, or grains. Chronic irritation from food sensitivities can cause loose stool, mucus, or blood over time.
Switching to a hypoallergenic or limited-ingredient diet under your vet’s guidance can help determine whether food intolerance is behind your dog’s symptoms.
Intestinal Injury or Foreign Object
If your dog swallows something sharp, such as a stick, bone shard, or toy fragment, it can injure the lining of the stomach or intestines. This may cause both vomiting and bloody diarrhea.
Foreign bodies often cause discomfort, lethargy, and loss of appetite. If you suspect your dog has ingested a non-food object, contact your vet immediately — X-rays or an ultrasound may be necessary.
Stress
Stressful events like travel, boarding, loud noises, or changes in routine can disrupt your dog’s digestion, leading to colitis — inflammation of the colon.
This stress-induced condition often results in loose stool with small amounts of bright red blood or mucus.
Providing a calm environment and avoiding major changes during stressful periods can help prevent flare-ups.
Read more: Dog Loose Stool But Not Diarrhea (What it means)
What to Do if Your Dog Has Loose Stool with Blood
If your dog’s stool is loose but they’re still active and eating normally, you can take a few initial steps at home:
Withhold food for 12–24 hours (while ensuring access to fresh water) to let the digestive system rest.
Gradually reintroduce food with a bland diet of boiled chicken and rice for 1–2 days.
Monitor your dog’s hydration — dehydration can occur quickly with diarrhea.
However, if symptoms persist or worsen, veterinary evaluation is crucial. Your vet may perform:
Fecal testing for parasites or bacteria.
Bloodwork to assess infection or organ health.
Imaging (X-rays or ultrasound) to check for obstruction or injury.
When to Call or Visit the Vet
Call your veterinarian immediately if your dog shows any of the following:
Continuous bloody diarrhea for more than 24 hours.
Vomiting along with blood in the stool.
Lethargy, loss of appetite, or collapse.
Signs of dehydration (dry gums, sunken eyes, excessive panting).
Black, tarry stool (a sign of internal bleeding)
These symptoms may indicate a serious underlying issue like parvovirus, pancreatitis, or intestinal bleeding, all of which need urgent medical care.
Prevention Tips
Feed a consistent, high-quality diet and avoid frequent food changes.
Prevent scavenging by supervising outdoor play and keeping garbage secured.
Stay on top of deworming and vaccinations to protect against common infections.
Limit stress and provide a stable environment, especially after major changes.
Schedule regular vet checkups to catch digestive problems early.
Read more: Old Dog Loose Stool (Common Causes)
Key Takeaway
Seeing blood in your dog’s loose stool can be scary, but it’s not always a sign of something severe. Minor dietary upsets can resolve quickly, but persistent or severe cases should always be checked by a vet.
Early intervention often prevents complications and ensures your dog’s digestive system returns to normal swiftly.