Is blood in dog poo always an emergency?

Not always, but it always warrants a call to your vet. It becomes an emergency when it comes with vomiting, lethargy, pale gums, a painful belly, large volumes of blood, or in a young puppy.

What does black tarry dog poo mean?

It usually means digested blood from higher in the digestive tract, which is generally more concerning than fresh red blood. It is easy to miss because it does not look like blood, so it is worth knowing about.

My dog has bloody diarrhoea but seems fine — do I still call?

Yes. Dogs compensate well and can look bright while something significant is going on. A call costs nothing and lets your vet decide how quickly they need to see them.

Can I treat blood in my dog’s stool at home?

No. The causes range from minor to serious and cannot be distinguished at home, and some home remedies make things worse. Ring your vet.

Blood in your dog’s poo — what it means

Blood in a dog’s stool always warrants a call to your vet. It is not always an emergency, but it is never something to watch and wait on for days — and the colour tells you something useful before you even pick up the phone.

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This is worth a call to your vet rather than waiting to see how it goes, particularly if it has lasted more than a day or your pet is otherwise off-colour.

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Red blood and black stools are not the same thing

Fresh red blood, sometimes with mucus, generally comes from the lower gut — the colon or rectum. It often looks alarming and is frequently the less serious of the two, but it still needs assessing.

Black, tarry, sticky stool is digested blood from higher up the digestive tract, and it is the more concerning presentation. It can be difficult to recognise because it does not look like blood at all.

If you can, photograph it. It is a grim job and it is genuinely the most useful thing you can bring to the appointment.

Ring straight away if

Your dog is also vomiting, is lethargic or collapsed, has pale gums, has a painful or swollen belly, or is passing large amounts of blood. That combination can indicate serious illness and needs same-day attention.

They may have eaten something they should not have — a bone, a toy, a corner of a sock, rat poison, or a human medicine. Do not wait to see how it develops.

They are a young puppy. Puppies deteriorate quickly and several causes of bloody diarrhoea are far more dangerous in them.

What can cause it

Common causes include dietary indiscretion, parasites, infections, inflammation of the gut, and straining from constipation or an anal gland problem. Some are minor and some are not, and they cannot reliably be told apart at home.

More serious possibilities include a foreign body, poisoning, a clotting problem, and disease elsewhere in the body. This is precisely why the advice on this page is to ring rather than to try a remedy.

What to have ready

When the blood started and how many times it has happened. Whether it is fresh red or black and tarry. Whether your dog is eating, drinking, and behaving normally.

Their worming and vaccination status, any medication they are on, and anything they might have eaten in the last few days.

We are not going to recommend a product on this page. There is nothing you can buy that is a sensible response to blood in a dog’s stool, and the right next step is a phone call.

Common questions

Is blood in dog poo always an emergency?: Not always, but it always warrants a call to your vet. It becomes an emergency when it comes with vomiting, lethargy, pale gums, a painful belly, large volumes of blood, or in a young puppy.
What does black tarry dog poo mean?: It usually means digested blood from higher in the digestive tract, which is generally more concerning than fresh red blood. It is easy to miss because it does not look like blood, so it is worth knowing about.
My dog has bloody diarrhoea but seems fine — do I still call?: Yes. Dogs compensate well and can look bright while something significant is going on. A call costs nothing and lets your vet decide how quickly they need to see them.
Can I treat blood in my dog’s stool at home?: No. The causes range from minor to serious and cannot be distinguished at home, and some home remedies make things worse. Ring your vet.

Sources

Written against guidance published by UK veterinary and welfare organisations. Always confirm specifics with your own vet.

Written by Matt Garnett, who runs Giddy Pets and is a lifelong pet owner — not a vet. This is general information, not veterinary advice, and it cannot replace an examination by the vet who knows your animal. How we write these guides.