Symptom · Dogs
Blood in dog poo: what it means and when to call the vet
A streak of fresh red blood in an otherwise well dog often comes from an irritated large bowel. Large amounts of blood, raspberry-jam diarrhoea, black tarry stools, or blood with vomiting and lethargy need a vet the same day.
By Maya HartCommon causes
- Colitis from stress or scavenging
- Sudden diet changes
- Parasites such as whipworms and giardia
- Acute haemorrhagic diarrhoea syndrome (AHDS)
- Parvovirus
- Stomach ulcers from anti-inflammatory drugs (black stools)
- Rat poison (anticoagulant rodenticides)
- Polyps or tumours
What you can do at home
- For a single streak in a bright dog: bland food in small meals for a day or two
- Make sure fresh water is available
- Keep a sample or a photo for your vet
- Don’t give human anti-diarrhoea medicines
What the vet may do
- Examine and check hydration
- Faecal tests for parasites and parvovirus
- Blood tests including clotting times
- Fluids, anti-nausea medicines and probiotics
Prevention
- Regular worming
- Vaccinate puppies against parvovirus
- Change foods gradually
- Stop scavenging
The details
The colour of the blood tells vets where it came from. Bright red blood usually comes from the large bowel or rectum, where colitis — often after a dog has eaten something unsuitable or had a stressful few days — is the commonest cause. Black, tarry stools mean blood has been digested, pointing to bleeding higher up, such as a stomach ulcer, and are more serious.
Dogs with sudden, heavy bloody diarrhoea can become dehydrated within hours and need prompt treatment.
Questions owners ask
Is blood in dog poo an emergency?
Usually it is not an emergency, but your pet should see a vet within 24 hours. Go now if you see: large amounts of blood, or diarrhoea that looks like raspberry jam; black, tarry stools (digested blood); blood with vomiting, weakness or pale gums; unvaccinated puppies with bloody diarrhoea (possible parvovirus); possible rat poison exposure.
What causes blood in dog poo?
Colitis from stress or scavenging; Sudden diet changes; Parasites such as whipworms and giardia; Acute haemorrhagic diarrhoea syndrome (AHDS); Parvovirus; Stomach ulcers from anti-inflammatory drugs (black stools); Rat poison (anticoagulant rodenticides); Polyps or tumours.
What can I do at home?
For a single streak in a bright dog: bland food in small meals for a day or two. Make sure fresh water is available. Keep a sample or a photo for your vet. Don’t give human anti-diarrhoea medicines.
Sources
Tailwise is for general information and is reviewed by veterinary professionals, but it is not a substitute for advice from your own vet, who knows your pet. How we check facts