# Blood Clots in Dog Poop: Causes and What to Do A blood clot in dogs poop is a sign of bleeding somewhere in the lower digestive tract, most often the colon or rectum. Clots look like small dark red or maroon jelly-like pieces mixed into the stool, and they often come with mucus. A clot by itself is not a diagnosis, so the real question is what is causing the bleeding and how much blood is being lost. This article is educational and is not a substitute for veterinary diagnosis or treatment. ## Quick Answer - Small streaks of bright red blood or tiny clots on the surface of firm poop are common with irritation in the lower bowel, and many of these cases are mild and short-lived. - Large amounts of blood, clots the size of a grape or bigger, or black tarry stool point to heavier bleeding and need same-day veterinary care. - Mucus and blood together usually mean inflammation in the colon, which vets call colitis, and it often causes urgency, straining, and frequent small poops. - Hookworms are a common cause of bloody stool in US dogs, and drug-resistant hookworms are now widespread across the country [1]. - Do not give human anti-diarrheal or pain medications to your dog. Some are toxic to dogs, and dosing is not something you can guess. ## What Blood Clots in Dog Poop Look Like Fresh blood in stool is called hematochezia. It ranges from a few red streaks on the outside of a normal stool to a stool that is mostly blood. Clots form when blood sits in the bowel long enough to congeal, so they usually signal bleeding in the colon, rectum, or anus instead of the stomach or upper small intestine. Mucus is a clear or cloudy gel that the colon makes to protect its lining. When the colon is inflamed, it produces more mucus, so you may see shiny coating, stringy gel, or mucus mixed with blood and clots. That combination is a classic pattern for colitis. Blood from higher up in the digestive tract looks different. It is partly digested, so it comes out as black, tarry stool called melena. Melena is not the same as a clot, and it usually means a larger or more serious bleed. ### What Is Normal and What Is Not A single tiny red streak on one stool, with a dog that is eating, drinking, and acting normal, is often minor. Watch it closely for 24 hours. These are not normal and should prompt a call to your vet: - More than a streak or two of blood - Visible clots - Blood plus mucus for more than a day - Bloody diarrhea - Black tarry stool - Any blood with vomiting, weakness, or belly pain If your dog has blood in the stool but seems completely fine otherwise, that still deserves a veterinary conversation. You can read more about that specific pattern in [Dog Pooping Blood but Acting Normal: What to Do](/knowledge/veterinary-medicine/digestive-and-urinary-care/dog-pooping-blood-acting-normal). ## Main Causes of Blood Clots in Dog Poop Most clots come from inflammation, infection, or injury in the lower bowel. Less often, they come from a bleeding disorder or a problem with blood clotting itself. A thrombus is a blood clot that forms when blood flow is restricted, when a blood vessel lining is damaged, or when a condition makes a dog produce clots excessively [2]. Those clots form inside blood vessels and the heart, not in the stool. They can block vessels where they form, or break loose and lodge somewhere else as an embolus [2]. So a clot in poop is almost always a sign of local bleeding in the gut, not a traveling clot from elsewhere. | Cause | Typical clues | How urgent | |---|---|---| | Colitis (colon inflammation) | Mucus, small frequent poops, straining, urgency, clots mixed with gel | Same-day to 24 hours | | Hookworm infection | Weight loss, pale gums, diarrhea, melena or hematochezia, poor coat | Same-day | | Other parasites (whipworms, giardia) | Chronic intermittent diarrhea, mucus, weight loss | Routine to same-day | | Viral enteritis (parvovirus, others) | Sudden severe diarrhea, vomiting, lethargy, not eating | Emergency now | | Dietary upset or food intolerance | Recent diet change, garbage eating, soft stool with streaks | 24 hours, sooner if worse | | Foreign body or obstruction | Vomiting, belly pain, no poop or small bloody poop | Emergency now | | Anal gland or rectal injury | Blood on surface, licking the rear, pain when pooping | Same-day | | Bleeding disorder or clotting problem | Bleeding from other sites, bruising, pale gums | Emergency now | | Severe dental or oral disease | Blood swallowed from the mouth, melena, bloody saliva | Same-day | ### Colitis and Inflammatory Bowel Disease Colitis is the most common reason owners see mucus and blood together. The colon lining becomes inflamed, so it bleeds easily and makes extra mucus. Dogs with colitis often strain to poop, go frequently, and produce small amounts with clots or jelly-like material. Inflammation can also affect the stomach and small intestine at the same time. One report described a dog with chronic gastritis, enteritis, and colitis found on biopsy after presenting with vomiting and hematochezia [3]. That case involved a rare stomach problem, but it shows how bleeding in the gut often comes from inflammation in more than one segment. If your dog has both blood and mucus in loose stool, see [Dog Diarrhea with Blood and Mucus: What It Means and What to Do](/knowledge/veterinary-medicine/digestive-and-urinary-care/dog-diarrhea-blood-mucus-causes). ### Parasites, Including Drug-Resistant Hookworms Ancylostoma caninum, the canine hookworm, is the most common and most clinically important gastrointestinal worm in US dogs. Acute infections cause anemia, melena, hematochezia, dehydration, and poor weight gain or weight loss [1]. Hookworms attach to the gut lining and feed on blood, so they can cause both fresh blood and black stool. This matters more now than it did a decade ago. Resistance to fenbendazole, moxidectin, and pyrantel pamoate has been documented in A caninum in the US, and resistant cases are being reported more often in the US and Canada [1]. Resistance is no longer limited to Greyhounds. National studies have found drug-resistant hookworms in dogs of all sizes, ages, and breeds, at high prevalence in every region of the continental US [1]. That means a stool sample and proper follow-up testing matter. A single deworming may not clear the infection. ### Viral and Bacterial Causes Viruses are a major cause of gastrointestinal disease in dogs worldwide, and routine testing does not catch all of them. A UK study of 80 diarrheic dogs found 12 viruses known to infect canids, including canine sapovirus and canine minute virus, which have been linked to gut disease [4]. The clinical relevance of some newly detected viruses, such as bufavirus and rotavirus C, is still unclear [4]. Parvovirus remains the classic emergency. It causes severe bloody diarrhea, vomiting, and rapid dehydration, and it can kill an unvaccinated puppy within days. ### Bleeding From the Mouth or Elsewhere Sometimes the blood is not coming from the bowel at all. A dog can swallow blood from the mouth, nose, or throat, and it shows up in the stool as melena or dark material. One report described two dogs with severe bleeding after the inferior alveolar artery in the jaw was cut by advanced periodontal disease. Both were anemic on arrival, with packed cell volumes of 21% and 20%, and one was in hemorrhagic shock. Both had melena and hematemesis, and both needed anesthesia and surgical ligation to stop the bleeding [5]. Severe dental disease is not just a mouth problem. ### Blood Clots in the Bladder Owners sometimes search for "blood clot in dogs bladder" because they see blood in urine or in the diaper area and are not sure which end it came from. Blood in urine looks different from blood in stool. Urine with blood is usually pink, red, or tea-colored, and clots in urine can be irregular and stringy. If you cannot tell whether the blood is coming from poop or pee, collect a sample of each if you can, and call your vet. ## Red Flags That Mean Emergency Care Now Go to an emergency clinic right away if you see any of these: - Large volumes of blood or clots bigger than a grape - Black tarry stool - Bloody diarrhea with vomiting - Pale, white, or gray gums - Weakness, collapse, or trouble standing - Fast breathing or a racing heart - Belly that looks swollen or feels painful - A puppy with bloody diarrhea, especially if unvaccinated - Bleeding from the gums, nose, or a wound that will not stop Anemia from gut bleeding can develop quickly, and a dog can look fine in the morning and be in shock by evening. Do not wait to see if it improves on its own when these signs are present. ## What You Can Safely Do at Home While You Wait Home care is about keeping your dog stable and collecting information, not treating the bleeding. - Withhold food for a short time only if your vet tells you to. Puppies and small dogs should not fast for long. - Keep fresh water available. Dehydration is a real risk with diarrhea. - Collect a fresh stool sample in a clean bag or container. Your vet can test it for parasites and other causes. - Take a photo of the stool and the clots. Color and amount help your vet judge urgency. - Note the time each episode happened and what the stool looked like. - Check your dog's gums. They should be pink and moist. Press gently and see how fast the color returns. - Do not give human medications such as ibuprofen, naproxen, aspirin, or loperamide. Some are toxic to dogs. - Do not give any dewormer or antibiotic you have at home without veterinary guidance. If your dog is bright and eating but has a small amount of blood, a routine visit within a day or two is reasonable. If your dog is dull, not eating, or vomiting, that is same-day care. For more on sorting mild from serious, see [Dog Blood in Stool: Home Care and When to Call the Vet](/knowledge/veterinary-medicine/digestive-and-urinary-care/dog-blood-in-stool-home-care). ## What Your Veterinarian Will Check and Test Your vet will start with a full physical exam, including gum color, hydration, belly palpation, and a rectal exam. They will ask about diet, medications, travel, boarding, and whether your dog eats garbage or hunts. Common tests include: - Fecal flotation and antigen testing for hookworms, whipworms, giardia, and other parasites - Fecal PCR for viral and bacterial causes - Blood work, including a complete blood count to check for anemia and a chemistry panel - Coagulation testing if a bleeding disorder is suspected - Abdominal imaging, such as X-rays or ultrasound, if a foreign body, mass, or intussusception is possible - Endoscopy or biopsy in chronic cases Imaging can catch problems that blood work misses. In one case, a dog with vomiting and hematochezia was diagnosed with a rare gastric intussusception using ultrasound and CT, then treated endoscopically without surgery [3]. That is an uncommon diagnosis, but it shows why imaging is used when signs do not fit a simple colitis picture. Gastrointestinal signs after major surgery are also common and often short-lived. In a study of 126 dogs having cervical spine surgery, 23% developed GI signs, including diarrhea, regurgitation, hematochezia, and melena. Signs lasted 1 to 2 days in 85% of those dogs [6]. If your dog has recent surgery and then bloody stool, tell your vet, because timing matters. Treatment depends on the cause. It may include deworming, antibiotics, anti-inflammatory drugs, a prescription diet, fluids, or hospitalization. If your dog is anemic from blood loss, a transfusion may be needed, as in the two dental bleeding cases where packed red blood cells were given [5]. ## Prevention and Monitoring You cannot prevent every cause of bloody stool, but you can lower the odds. - Keep your dog on year-round parasite prevention. Because resistant hookworms are widespread, ask your vet which product and testing schedule fits your region [1]. - Pick up poop promptly and wash your hands. Some causes, including hookworms, can affect people. - Keep vaccines current, especially parvovirus and distemper. - Feed a consistent diet and introduce new foods slowly. - Keep trash, bones, string, and small toys out of reach. - Brush your dog's teeth or use vet-approved dental care. Severe periodontal disease can cause serious bleeding [5]. - Watch for early signs such as mucus, straining, or a change in stool frequency. If your dog has had bloody stool once and recovered, keep an eye on the next few poops. Recurring clots, mucus, or weight loss point to a chronic problem that needs a workup. ## Limitations and When to Contact a Veterinarian This article cannot tell you what is causing your dog's bleeding. Only a veterinarian who examines your dog and runs tests can do that. Individual cases need a veterinarian, and the right timing depends on how sick your dog looks. Call your vet the same day if you see clots, more than a streak of blood, mucus with blood for more than a day, or any blood in a puppy or senior dog. Go to an emergency clinic now if you see heavy bleeding, black tarry stool, vomiting with bloody diarrhea, pale gums, weakness, collapse, or a painful or swollen belly. Schedule a routine visit if you saw a tiny streak once, your dog is acting completely normal, and there has been no repeat. Even then, mention it at your next appointment so it stays on the record. ## Frequently Asked Questions ### Is a blood clot in dog poop always an emergency? No, not always. A small clot with a normal-acting dog may be mild colitis or a minor irritation. Large clots, heavy bleeding, black stool, vomiting, or weakness are emergencies and need care right away. ### Can worms cause blood clots in dog poop? Yes. Hookworms attach to the gut lining and feed on blood, which can cause fresh blood, black stool, and anemia. Drug-resistant hookworms are now common across the US, so testing and follow-up matter more than a single deworming. ### What does mucus with blood in dog poop mean? It usually means the colon is inflamed, a pattern vets call colitis. The inflamed lining makes extra mucus and bleeds easily, causing urgency, straining, and small frequent poops. Parasites, diet upset, and stress can all trigger it. ### Can my dog pass a blood clot from the bladder in its poop? No. Clots from the bladder come out in urine, not stool. If you see blood and cannot tell which end it came from, collect a urine sample and a stool sample separately and bring both to your vet. ### Should I fast my dog if there is blood in the stool? Only if your veterinarian tells you to. Short fasting sometimes helps with mild diarrhea in adult dogs, but puppies and small dogs can get low blood sugar quickly. Offer water and call your vet for guidance. ## Related Articles - [Dog Pooping Blood but Acting Normal: What to Do](/knowledge/veterinary-medicine/digestive-and-urinary-care/dog-pooping-blood-acting-normal) - [Blood in dog stool causes urgency and veterinary evaluation](/knowledge/veterinary-medicine/emergency-care/blood-in-dog-stool) - [Dog Diarrhea with Blood and Mucus: What It Means and What to Do](/knowledge/veterinary-medicine/digestive-and-urinary-care/dog-diarrhea-blood-mucus-causes) - [Dog Blood in Stool but Acting Normal: What Does It Mean?](/knowledge/veterinary-medicine/digestive-and-urinary-care/dog-blood-in-stool-acting-normal) - [Dog Blood in Stool: Home Care and When to Call the Vet](/knowledge/veterinary-medicine/digestive-and-urinary-care/dog-blood-in-stool-home-care) - [Why Is My Dog Pooping blood? HGE, Parvovirus & Emergency Protocol](/knowledge/veterinary-medicine/symptom-guides/why-is-my-dog-pooping-blood-hge-parvovirus-emergency-protocol) - [Why Is My Dog's Poop Like Jelly With Blood?](/knowledge/veterinary-medicine/digestive-and-urinary-care/dog-poop-jelly-blood) - [Mucus in Dog Poop: Causes and When to Worry](/knowledge/veterinary-medicine/digestive-and-urinary-care/mucus-in-dog-poop) - [Blood in Dog Urine or Stool: Treatment Options](/knowledge/veterinary-medicine/digestive-and-urinary-care/blood-in-urine-stool-dogs-treatment) - [Canine Intestinal Parasites Causing Diarrhea: Diagnosis, Treatment, and Prevention](/knowledge/parasites/pet-parasites/dog-intestinal-parasites-diarrhea) ## References 1. [American Association of Veterinary Parasitologists Hookworm Task Force review on best practices for diagnosis and treatment of multidrug-resistant hookworms](https://pubmed.ncbi.nlm.nih.gov/42102862/). Journal of the American Veterinary Medical Association, 2026. 2. [Blood Clots and Aneurysms in Dogs - Dog Owners](https://www.merckvetmanual.com/dog-owners/heart-and-blood-vessel-disorders-of-dogs/blood-clots-and-aneurysms-in-dogs). Merck Veterinary Manual. 3. [Endoscopic reduction of true gastrogastric intussusception in a dog](https://pubmed.ncbi.nlm.nih.gov/42585566/). Journal of veterinary internal medicine, 2026. 4. [Expanded detection of canine enteric viruses in UK dogs with diarrhoea](https://pubmed.ncbi.nlm.nih.gov/42709036/). Microbial genomics, 2026. 5. [Severe Hemorrhage Requiring Transfusion in Two Dogs Following Right Inferior Alveolar Artery Laceration Secondary to Severe Periodontitis](https://pubmed.ncbi.nlm.nih.gov/42703907/). Journal of veterinary emergency and critical care (San Antonio, Tex. : 2001), 2026. 6. [Gastrointestinal complications occur in dogs with intervertebral disk herniation undergoing ventral slot decompression but are mostly self-limiting](https://pubmed.ncbi.nlm.nih.gov/42061462/). Journal of the American Veterinary Medical Association, 2026. ## Further Reading - [American Veterinary Medical Association: First Aid Tips for Pet Owners](https://www.avma.org/resources-tools/pet-owners/emergencycare/first-aid-tips-pet-owners) - [Merck Veterinary Manual: Dog Owners](https://www.merckvetmanual.com/dog-owners) - [Cornell Richard P. Riney Canine Health Center: Canine Health Information](https://www.vet.cornell.edu/departments-centers-and-institutes/riney-canine-health-center/canine-health-information)