Symptom: Blood in Stools – When Should I Contact a Vet?
Blood in stools can vary from a few bright red streaks to black, tarry faeces. Although a small amount of fresh blood is not always an emergency, blood in the stool should never be ignored, especially if your pet is unwell.
You may notice:
Bright red blood coating the stool or passed separately
Black, tarry stools, which may indicate bleeding higher up in the digestive tract
Blood mixed throughout otherwise normal stools
Diarrhoea containing blood or mucus
Straining to pass faeces or passing only small amounts
'My pet has blood in their poo' - Frequently asked questions
What are the common reasons that my pet has blood in their poo?
- Dietary upset: eating something unusual or a sudden change in diet can irritate the bowel and cause fresh blood in the stool.
- Parasites or infections: worms, bacteria and viruses can all cause inflammation of the intestines and bloody diarrhoea.
- Inflammatory bowel disease (IBD): long-term inflammation of the digestive tract can cause recurring diarrhoea and blood in the stool.
- Foreign bodies or intestinal disease: swallowed objects, bowel obstructions, ulcers and other diseases of the digestive tract can all cause bleeding.
- Tumours or bleeding disorders: some cancers and conditions affecting blood clotting can lead to blood in the stool.
DOs - My pet has blood in their poo, what to do at home:
- If your pet is passing large amounts of blood, has black tarry stools, or seems unwell, contact your vet immediately.
- Keep your pet well hydrated and encourage them to rest.
- Monitor your pet closely for vomiting, lethargy, loss of appetite or worsening diarrhoea.
- Arrange an appointment with your vet, even if there is only a small amount of blood, particularly if it persists or keeps returning.
DON'Ts - My pet has blood in their poo, what not to do at home:
- Don't ignore blood in your pet's stool, especially if it continues or your pet seems unwell.
- Don't give human medications unless specifically advised by your vet.
- Don't make sudden changes to your pet's diet, unless your vet recommends it.
- Don't delay contacting your vet if your pet develops additional signs such as vomiting, weakness or abdominal pain.
My pet has blood in their poo - when is it an emergency?
Seek immediate veterinary attention if your pet:
- Passes large amounts of blood or has black, tarry stools.
- Has blood in the stool together with vomiting, weakness, collapse, pale gums or abdominal pain.
- Is a puppy or kitten or has an underlying medical condition.
- Continues to pass blood or becomes increasingly unwell.
A small amount of fresh blood is not always an emergency, but it should still be assessed by your vet, especially if it persists or recurs.
Written by Gill Burkhill, Veterinary Surgeon, Animal Trust Vets CIC | Published July 2026 | Review date July 2029 | This advice is for UK pets only and is not a replacement for seeing a vet