Black, tarry stool in dogs can mean digested blood, which usually comes from higher in the digestive tract.
That makes it a reason to see a vet the same day.
If you cannot tell the two apart, see a vet today rather than waiting.
What does black stool look like?
The AKC guide to blood in dog poop explains why sticky, dark stool needs a closer look.
| Stool type | What you see | What to do |
|---|---|---|
| Tarry black stool | Sticky, shiny, and tar-like | See a vet today |
| Dark brown stool | Darker than usual | Contact your vet and log the diet |
| Bright red blood | Red on or around the stool | See a vet promptly |
| Dark stool with weakness | Lethargy or pale gums | Go to an emergency clinic |
Can food cause dark stool?
Yes.
Dark foods, organ meats, and some medicines can darken stool without any blood.
Write down when you first noticed the color, so your vet knows how long it has lasted.
How can you tell the difference at home?
- Check the texture and shine
- Note whether it smears or sticks
- Review what your dog ate in the last 2 days
- Check energy, appetite, and gum color
- Take a photo in daylight before the stool changes
Why does black stool need a vet?
Digested blood points to bleeding somewhere in the stomach or intestines.
Several causes can lead to that bleeding, and each one needs a different response.
The Merck Veterinary Manual on stomach and intestinal disorders in dogs covers why vets test for the source.
What should you tell the vet?
- Every medication, including pain relievers and anti-inflammatories such as NSAIDs
- Recent foods, treats, and table scraps
- When the stool started and how often it happens
- Vomiting, weakness, or appetite changes
After the vet has found the cause, a daily supplement like Plentum Advanced K9 Gut Restore can support normal bowel function.
When should you call the vet?
- Black, tarry, or sticky stool of any amount
- Bright red blood in or on the stool
- Vomiting, especially with blood or coffee-ground material
- Weakness, collapse, or pale gums
- Refusal to eat or drink
- Belly pain or a tense abdomen
- Any dark stool in a puppy or senior dog
Call your vet today for any black, tarry stool, and go to an emergency clinic if your dog collapses or looks weak.
For the full picture on stool changes, read the dog digestive health and stool guide.
You can also compare mucus in dog stool and yellow stool in dogs, since color changes often come with other clues.
Sources
- AKC: Blood in Dog Poop: Signs, Symptoms and Treatment
- Merck Veterinary Manual: Disorders of the Stomach and Intestines in Dogs
- AKC: Is Pepto-Bismol Safe For Dogs?
Frequently asked questions
Is black stool always a sign of bleeding?
Not always.
Diet can darken stool, but tarry, sticky stool needs a vet to rule out digested blood.
Can a puppy have black stool?
Puppies should be checked the same day for black or tarry stool.
They have less reserve, so a problem can get worse faster.
What should I bring to the vet?
Bring a photo of the stool, a list of foods and medications, and the time the color changed.
Should I wait to see if the stool passes?
No.
Black, tarry stool is a reason to see a vet the same day, even if your dog seems fine.
