Jump to section

What are Passing Black Stools?

It is vital to be aware of the consistency and color of your pet’s feces for the sake of his health. While your dog cannot tell us verbally what is wrong with him, by being observant, you can read the tell-tale signs if a health issue arises. If your dog has started passing black tarry stools, then it indicates the presence of digested blood in the feces, known as melena. For the stool to appear black, there must be a significant amount of bleeding into the stomach or small intestines. Note that bleeding into the colon or rectum (hematochezia) appears as fresh blood in the stool. Any amount of internal bleeding is a serious concern. The passing of black stools could occur due to any of the following conditions: 

Compare Pet Insurance & Wellness Plans

Save up to $273 per year

Compare plans
advertisement image

Why Passing Black Stools Occurs in Dogs

Injury to your Dog’s Digestive System

 

A black, tarry stool (often very smelly) indicates that there is old blood somewhere in your dog’s upper digestive system, and internal bleeding is a concern. It may stem from an injury to the GI tract from the indiscriminate eating that some dogs are famous for, such as the ingestion of sharp twigs, parts of toys, and other random items.

Infectious Agents 

Intestinal disorders such as intestinal parasites, bacterial, viral, or fungal infections need to be ruled out as the cause. Any of these agents can cause internal bleeding within the stomach or small intestine. The vet may run some tests such as an abdominal scan ,endoscopy and stool analysis to diagnose an infection. Needless to say, it needs a veterinarian’s intervention and care. 

Hemorrhagic Gastroenteritis or Acute Hemorrhagic Diarrhoea Syndrome

While the cause of hemorrhagic gastroenteritis is currently unknown, it needs immediate treatment to prevent your dog from dehydration and to prevent death; it is a very serious condition. The diagnosis is likely to be confirmed with a blood test. If your dog has this condition, the tests will reveal elevated packed cell volume levels (PCV). 

Gastrointestinal Ulceration 

If your dog is experiencing this condition, it can be caused by one of the three most common causes: hepatic (liver) disease, the use of non-steroidal anti-inflammatory drugs and neoplasia, which is the abnormal growth of cells. Your dog may show no other signs of discomfort, or they may experience a lack of appetite, weakness and pain in their abdomen. There are many causes for this condition, and it needs instant attention from a veterinarian.

Cancer

 

No one wants their beloved dog to be diagnosed with cancer, but unfortunately, it can happen. It is common knowledge that the sooner cancer is found, the better chances of successful treatment and extending your dog’s life. While the passing of black stools does not necessarily indicate cancer, the quicker you can have it checked by a veterinarian the better for your dog. Observing your dog and noticing any symptoms is important, so if your dog has behavioral changes, chronic vomiting or diarrhoea, lethargy, loss of appetite or unexplained weight loss then it is advisable to get them to the clinic for a few diagnostic tests.

Clotting Disorders

When a dog's blood does not clot as it should, we can see bleeding from any region, including the upper digestive tract. Clotting disorders can have many causes including rat bait ingestion or Von Willebrand's disease.

arrow-up-icon

Top

What to do if your Dog is Passing Black Stools

The first thing to do is to take your dog for an immediate physical examination with your veterinarian as black stools are an indication that all is not right. If you can take a sample of the stool to show the vet, it may help in the diagnosis. Treatment and cost are determined as to the illness that your dog may be experiencing. 

If your dog has eaten something that is causing the internal bleeding (due to a sharp or pointed object), it may be that your dog needs surgery to remove the offending object. Your pet may need a few days in the hospital after the operation but should recover quickly. Some patients will be kept in the hospital for monitoring for several days after.

In the case that your dog is suffering an infectious condition or is battling with parasites, a course of the appropriate medication will help overcome it. Often, your dog will have a follow up examination and tests to determine if the medications have been effective. 

For hemorrhagic gastroenteritis, we don't always get a definitive diagnosis as to the cause. To help diagnose the ailment, your dog will require imaging, stool analysis and blood tests. Causes of HGE can include allergic reactions, clostridial infections and toxin ingestion. 

As dogs mature they can be more prone to gastrointestinal cancer, and it depends on the type of cancer as to how much your dog will be affected health wise. Your veterinarian will do blood tests, x-rays, and a complete physical examination of your dog to determine the extent of the damage. If a mass is located,  it is usually sampled to determine if it is benign or malignant. A biopsy can be done via an endoscopy, or a biopsy can be surgical (via an exploratory laparotomy). These samples can help provide a diagnosis, enabling the vet to determine the best treatment. 

If your dog is suffering from gastric ulcers, you veterinarian will look at rehydration, ant acid medicine and fluids depending on the severity of the condition. Dietary changes require a soft, bland diet that is easy to digest, allowing healing to occur. Ulcers can be secondary to underlying disease such as kidney failure, so further tests may be indicated.

arrow-up-icon

Top

Prevention of Passing Black Stools

While it is hard to prevent every disease or condition that your dog may get,  a good health management program will help. Removing sticks, bones and hard toys that they chew on can prevent any accidents with swallowing sharp pieces. Try to discourage them from drinking out of stagnant bodies of waters and puddles, which can harbour infections. A healthy diet is always advised. Speak with your veterinarian to see what is best for your dog as some will require hypoallergenic diets. Keeping your dog fit and slender is better for their health. 

Keep your dog up to date with their vaccinations and a good quality parasite prevention. 

arrow-up-icon

Top

Cost of Passing Black Stools

Treatment costs can vary considerably depending on the nature of the illness and what needs to be done to help correct it. Dogs are natural born scavengers and can cause internal injury by eating something that is either sharp or indigestible. The expense for removal of a foreign body and follow-up treatment can average $2500. Bacterial infections can cost on average $1,600 if your dog becomes very unwell and hospitalisation is needed. Hemorrhagic gastroenteritis costs from $2000 upwards depending on the severity. Cancers can cost $2000 and more. The cost is always related to the degree of the treatment required.

arrow-up-icon

Top

*Wag! may collect a share of sales or other compensation from the links on this page. Items are sold by the retailer, not Wag!.

Written by hannah hollinger

Veterinary reviewed by: Linda S.

Published: 08/07/2017, edited: 04/16/2021

Passing Black Stools Questions and Advice from Veterinary Professionals

Need pet health advice? Ask a vet

question-icon-cta

Ask a Vet

dog-name-icon

dog-breed-icon

English Shepherd

dog-age-icon

Seven Months

pill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filled

Unknown severity

thumbs-up-icon

0 found helpful

pill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filled

Unknown severity

Has Symptoms

Black Stool

Hi! My dog has recently started having blackish stool. Should I be concerned? I included a picture.

Sept. 26, 2020

Owner

answer-icon

Dr. Michele K. DVM

recommendation-ribbon

0 Recommendations

Thank you for your question. . If this is still occurring, he may have a problem with GI bleeding. It would be best to have your pet seen by a veterinarian, as they can examine them, see what might be going on, and get treatment for them.

Oct. 17, 2020

Was this experience helpful?

dog-name-icon

dog-breed-icon

German Shepherd

dog-age-icon

Three Months

pill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filled

Unknown severity

thumbs-up-icon

0 found helpful

pill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filled

Unknown severity

Has Symptoms

Black Poop

My dogs poop has been black since changing his diet from kibble to kibble and wet food or kibble and cooked meats like beef, turkey, or chicken

Sept. 25, 2020

Owner

answer-icon

Dr. Michele K. DVM

recommendation-ribbon

0 Recommendations

Thank you for your question. I apologize for the delay, this venue is not set up for urgent emails. I hope that your pet is feeling better. If they are still having problems, It would be best to have your pet seen by a veterinarian, as they can examine them, see what might be going on, and get any testing or treatment taken care of that might be needed.

Oct. 21, 2020

Was this experience helpful?

dog-name-icon

dog-breed-icon

stafforshire terrier cross

dog-age-icon

Fourteen Years

pill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filled

Unknown severity

thumbs-up-icon

0 found helpful

pill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filled

Unknown severity

Has Symptoms

Tarry Stool

My dog appears healthy, however despite recently been supervised and fed three meals per day has failed to put on any weight. What does an occasional black tarry stool indicate?

Sept. 25, 2020

Owner

answer-icon

Dr. Michele K. DVM

recommendation-ribbon

0 Recommendations

Thank you for your question. I apologize for the delay, this venue is not set up for urgent emails. Tarry black stools often mean a bleeding problem in the upper GI tract. That may explain the weight loss, and It would be best to have your pet seen by a veterinarian, as they can examine them, see what might be going on, and get any testing or treatment taken care of that might be needed.

Oct. 21, 2020

Was this experience helpful?

dog-name-icon

dog-breed-icon

Jack Russell Terrier

dog-age-icon

Three Years

pill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filled

Unknown severity

thumbs-up-icon

0 found helpful

pill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filled

Unknown severity

Has Symptoms

Black/Blue Hard Stool

Hello, it has been about a week and my dog has black/blueish hard stool. Sometimes, it is normal color and texture and other times it is very dark and hard.

Sept. 24, 2020

Owner

answer-icon

Dr. Michele K. DVM

recommendation-ribbon

0 Recommendations

Thank you for your question. If your pet is still having problems, it would be best to have them seen by a veterinarian, as they will be able to examine them, see what might be going on, and get any treatment needed.

Oct. 24, 2020

Was this experience helpful?

dog-name-icon

dog-breed-icon

tea cup Chihuahua

dog-age-icon

Four Years

pill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filled

Unknown severity

thumbs-up-icon

0 found helpful

pill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filled

Unknown severity

Has Symptoms

Black Poop

my tea cup started acting strange...I don't if he ate something he shouldn't have...for the last two days he's been weak he's been restless he still eats and drinks but he popped black

Sept. 24, 2020

Owner

answer-icon

Dr. Michele K. DVM

recommendation-ribbon

0 Recommendations

Thank you for your question. I apologize for the delay, this venue is not set up for urgent emails. I hope that your pet is feeling better. If they are still having problems, It would be best to have your pet seen by a veterinarian, as they can examine them, see what might be going on, and get any testing or treatment taken care of that might be needed.

Oct. 25, 2020

Was this experience helpful?

dog-name-icon

Luke

dog-breed-icon

Labrador Retriever

dog-age-icon

7 Months

pill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filled

Fair severity

thumbs-up-icon

0 found helpful

pill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filled

Fair severity

Has Symptoms

Dark Poop

Hi I have a 7 months old Labrador Retriever, today he started to poop really dark (black) and kind watery. He is eating and drinking well, he’s really active. He was on a dewormer and diarrhea medication the past week. What I should do?

dog-name-icon

Sophie

dog-breed-icon

Fox terrier x chihuahua

dog-age-icon

12 Years

pill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filled

Moderate severity

thumbs-up-icon

0 found helpful

pill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filled

Moderate severity

Has Symptoms

Black Tarry Stools

Sophie is 12 yrs old she was diagnosed with Cushing disease last year..she now has black tarry stools she does not appear to be in pain or discomfort and eating and drinking well but seems to be a bit solace

dog-name-icon

Gus

dog-breed-icon

Pug

dog-age-icon

11 Months

pill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filled

Fair severity

thumbs-up-icon

1 found helpful

pill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filled

Fair severity

Has Symptoms

Dark Poop O

My dog has had poops that are black on outside but normal inside. I don’t think he has ate anything he’s not suppose to. He’s eating, drinking and playing normal, isn’t lethargic

dog-name-icon

Angel

dog-breed-icon

Chihuahua

dog-age-icon

9 Months

pill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filled

Fair severity

thumbs-up-icon

0 found helpful

pill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filled

Fair severity

Has Symptoms

Dark Stool

The first two days her stool was very dark and what she's passing was a lot more. Now it's a yellow looking color but her stool is coming out less. She did eat a little the second day buy now she won't eat, we do have to give her fluids by a dropper to keep her hydrated.The good thing about Angel is she still plays time to time and moves around but she lays down when she needs. Today she started throwing up this yellow stuff. She's an indoor door so she's not around other dogs but she with chew on anything that she finds in my kinds room so where always having to try to catch her on that. I'm really worried about her what could it be someone please help direct me.

dog-name-icon

Pop

dog-breed-icon

Dachshund

dog-age-icon

2 Years

pill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filled

Fair severity

thumbs-up-icon

0 found helpful

pill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filled

Fair severity

Has Symptoms

Stool
Poo

My dog has been fine and has been playing, drinking and eating as normal but today has passed two big stools and in one part of one of them there is a black streak running though it (rest of the stool was normal), phoned the vet who said she will be ok as the consistency is good and the black isn’t the whole way through. I’m still worried, any idea of what the black could be in such a small portion of the stool?

Compare Pet Insurance & Wellness Plans

Save up to $273 per year

advertisement image
Need pet insurance?