My dog has loose motion with blood: what should I do?
Updated By PetymFacts checked against official sources on
Quick answer
Call your vet today. Blood in the stool is one of PDSA's warning signs, and in a puppy, or a dog that is also vomiting, weak or off its food, go to a vet now. Parvovirus and acute haemorrhagic diarrhoea syndrome both cause bloody diarrhoea, dry a dog out fast and need a vet's fluid therapy.
Keep water available, do not give human medicines, and take a photo or a sample of the stool. Many adult dogs with a single streak of blood and no other signs recover, but only a vet can tell which kind your dog has.
When is bloody diarrhoea an emergency?
Go to a vet now, day or night, if any of these apply.
If A puppy, especially one under six months or not fully vaccinated.
Go now. Merck says young, unvaccinated or incompletely vaccinated dogs are the most susceptible to parvovirus, which often causes bloody diarrhoea. Merck Veterinary Manual
If Vomiting as well as bloody diarrhoea.
Go now. PDSA lists parvovirus and haemorrhagic gastroenteritis as causes of severe vomiting with bloody diarrhoea. PDSA
If Sudden, large amounts of bloody, watery diarrhoea in a small or toy breed.
Go now. Merck describes acute haemorrhagic diarrhoea syndrome as a sudden onset of profuse bloody diarrhoea, most often in small and toy breeds, and says prompt fluid therapy is the mainstay of treatment. Merck Veterinary Manual
If Lethargy, a painful tummy, refusing food, or constant watery diarrhoea.
Go today, not tomorrow. PDSA lists all of these as warning signs. PDSA
If A very old dog, a dog with an illness, or a dog on long-term medicine.
Call your vet the same day. PDSA says these dogs need advice sooner. PDSA
If You know or suspect it ate rat poison or another toxin.
Go now and take the packet. Cornell lists rat poison among the toxins that make dogs seriously ill. Cornell University College of Veterinary Medicine
What causes blood in a dog's loose motion?
Some causes are minor and some kill within days. They can look the same at home.
Canine parvovirus is the cause owners in India most need to think of. The Merck Veterinary Manual says early signs can be vague, such as fever or lethargy, and progress to vomiting and bloody diarrhoea within 24 to 48 hours. It spreads through contact with infected faeces and contaminated surfaces, and the virus survives indoors for at least two months and outdoors for many months. With good supportive care in a hospital, Merck reports that 70 to 90% of dogs survive, which is why speed matters.
Acute haemorrhagic diarrhoea syndrome, once called haemorrhagic gastroenteritis or HGE, comes on suddenly with profuse bloody diarrhoea, vomiting and a painful belly. Merck says small and toy breeds and young adult dogs are over-represented, and that the blood becomes very concentrated as the dog loses fluid. The prognosis is good with treatment and mortality is under 10% in hospitalised dogs, but it can be high if untreated.
Other causes PDSA lists include eating something unsuitable or rich, a sudden change of food, worms, Giardia, bacterial infections and colitis, which often shows as fresh blood and mucus. In puppies, TroCCAP warns that hookworms can cause diarrhoea that is often bloody, with anaemia and even death.
What should you tell or take to the vet?
A few details save time at the clinic.
- A photo of the stool, or a fresh sample in a clean bag or jar, so the vet can see the blood and test for worms or parvovirus. Merck Veterinary Manual
- When it started, how many times, and whether there was vomiting. PDSA
- The vaccination card: whether the puppy course and boosters are complete. Merck Veterinary Manual
- The deworming dates, because worms are a common cause in puppies. Tropical Council for Companion Animal Parasites
- Anything it may have eaten: scraps, rubbish, a new food, bones, a chewed packet. PDSA
- Any medicine your dog takes, especially anti-inflammatory painkillers, which PDSA flags. PDSA
What should you do at home while you arrange the vet?
Do
- Keep fresh water available. PDSA says dogs with diarrhoea need more water than usual to replace what they lose. PDSA
- Keep a puppy with possible parvovirus away from other dogs, and clean up with dilute bleach after removing the mess, as Merck advises for surfaces. Merck Veterinary Manual
- Wear gloves and wash your hands: hookworms can cause skin infections in people, TroCCAP says. Tropical Council for Companion Animal Parasites
- Only for a bright adult dog with mild diarrhoea under 24 hours, PDSA describes small bland meals. With blood, ask your vet first. PDSA
Don’t
- Give human anti-diarrhoea tablets or painkillers. Any medicine is the vet's decision. PDSA
- Starve a puppy, an old dog or a dog that is unwell. PDSA says fasting is not for these dogs. PDSA
- Expect antibiotics as a cure. The 2025 VetCompass study found antibiotic use stayed frequent despite years of advice against it for most cases. PLOS ONE (2025)study
- Wait for it to pass in a puppy. Parvovirus can move from vague signs to bloody diarrhoea within 24 to 48 hours. Merck Veterinary Manual
How common is it, and do most dogs recover?
Acute diarrhoea is one of the commonest reasons dogs see a vet. A 2025 Royal Veterinary College VetCompass study of UK dogs found a one-year incidence risk of 8.18%, and 29.32% of the cases were recorded as haemorrhagic, meaning there was blood. More than 80% of cases did not need a second visit, which suggests most settled quickly. Dogs under three and over nine years old were more likely to be affected.
That is reassuring for an adult dog that is bright and eating, but it says nothing about puppies with parvovirus, which this kind of study does not separate out. Treat blood as a reason to call, and let the vet decide how worried to be.
How do you prevent bloody diarrhoea?
Vaccinate. Merck recommends a modified live parvovirus vaccine for puppies, with boosters, and notes that maternal antibodies can interfere with early doses, so puppies are not fully protected until the course is done. Until then, keep a puppy away from places where unknown dogs toilet, such as roadside patches and society gardens, because the virus lasts for months in soil.
Deworm on your vet's schedule, change foods gradually, and keep rubbish, bones and rich festival food out of reach, since PDSA lists scavenging and sudden diet changes among the common causes. If you travel, give your sitter the vet's number and a clear rule: blood in the stool means a call to you and a trip to the vet the same day.
Going away soon? Tell us your dates.
A checked local sitter feeds, walks and keeps your pet company at home, follows your care sheet to the letter and sends a photo every day. Petym is opening city by city: send your dates and we will tell you when a sitter can take them.
- Meet your sitter first, free
- PAN-checked, first-aid trained
- A photo every day
- Pay through Petym, never cash
Questions owners ask
Is a little blood in my dog's stool an emergency?
- A single streak of fresh blood in an adult dog that is bright, eating and drinking is usually not an emergency, but call your vet that day. Go at once if the dog is a puppy, is vomiting, weak or off food, or passes large amounts of bloody, watery diarrhoea.
Can a puppy survive parvovirus?
- Many do with hospital care. The Merck Veterinary Manual says 70 to 90% of dogs with parvoviral enteritis survive with appropriate supportive care, and survival is best with intensive treatment. Without fluids and nursing the outlook is much worse, so take a puppy with bloody diarrhoea to a vet straight away.
What is HGE in dogs?
- HGE, now called acute haemorrhagic diarrhoea syndrome, is a sudden bout of profuse bloody diarrhoea, often with vomiting, most common in small and toy breeds. Merck says prompt intravenous fluids are the main treatment and the prognosis is good when treated, with mortality under 10% in hospitalised dogs.
Can I give curd or rice to a dog with bloody loose motion?
- Ask your vet first when there is blood. PDSA describes small, bland meals only for adult dogs with mild diarrhoea under 24 hours that are otherwise well. A dog with blood in its stool, vomiting or weakness needs a vet before any home feeding plan.
Can worms cause blood in a puppy's stool?
- Yes. TroCCAP, the tropical parasite council, says hookworms in puppies can cause diarrhoea that is often bloody, with anaemia, and can kill. Puppies need deworming on a schedule your vet sets, and a puppy with bloody diarrhoea needs a vet visit, not just a dewormer.
Keep reading
Free tools for this
Words on this page, explained
Sources
Each source was opened and read on the date shown. How Petym checks its sources
- Merck Veterinary Manual: Canine parvovirus infection (opens in a new tab)
- Merck Veterinary Manual: Acute hemorrhagic diarrhea syndrome in dogs (full review June 2025) (opens in a new tab)
- PDSA: Dog diarrhoea (May 2023) (opens in a new tab)
- Tropical Council for Companion Animal Parasites: Canine guidelines: hookworms (opens in a new tab)
- Cornell University College of Veterinary Medicine: Managing seizures (Riney Canine Health Center) (opens in a new tab)
- PLOS ONE (2025): Epidemiology and clinical management of acute diarrhoea in dogs under primary veterinary care in the UK (abstract read) (opens in a new tab)