Why Is My Dogs Anus Turning Black?

If you have recently noticed it, you might wonder: “why is my dogs anus turning black?” Your alarm is justified, there are several reasons why this is happening, and none of them are good for your dog.

Dogs are the most preferred option whenever people think about getting a pet. When you have a pet in your house, you need to take care of that animal just like a child. 

Usually, most pet owners prefer bringing a puppy, and as your little puppy starts growing into a fully grown dog, you might notice some unusual changes in your dog. One of these weird things that many dog owners notice is that as the pet begins to grow, the anus of the pet starts turning black. 

Why Is My Dogs Anus Turning Black

Various reasons can cause this change in your dog’s body, it can be changing in the color of the fur present in your dog’s body, or it might also be a problem related to the excretory system of your pet’s body. 

In this article, we will discuss all the possible reasons behind the black anus that you are witnessing in your dog’s body. We will also discuss other problems related to this issue here. So, read on and find out the answer to the question: “Why is my dog’s anus is turning black?”

Do Dogs Give Birth From Their Bum

No, they have a vagina and give birth through it. It has got nothing to do with the bum.

You may start noticing the black spot in your dog’s anus right after it has delivered puppies. It might make you think that the darkening of the anus is related to pregnancy and delivery, but dogs giving birth has nothing to do with the black spot developing in and around the anus. 

The anatomy of a dog is very similar to humans, and they deliver puppies through the vagina and not through the bum. Still, as a female dog’s vagina and bum are located in close proximity, that might make you think that they are giving birth through their bum. 

Why Has My Dog’s Bum Changed Colour?

There could be several reasons for this, including prolapse and perianal fistulas.

As your little puppy starts growing, the bum color of your dog may start changing, and as we are talking about the black coloration of the anus in your dog’s body, you should also know that your dog’s bum can change other colors such as dark brown, reddish-pink et cetera. 

Before discussing why a dog’s anus is turning black, we will discuss the root causes behind the change in color of your dog’s bum.

Why Is My Dogs Anus Turning Black

Diseases Related to Anal Sac

If the anal sac gets clogged or an infection occurs on any one of the sides of the anus, your dog can face problems in sitting. A yellowish fluid having a pungent odor will come out of the anal sac. This fluid can stick all around the bum and can make your dog’s bum look yellowish.

Perianal FIstula

When your dog reaches the age of 7, your dog can develop a perianal fistula, characterized by wounds all around the bum. 

A foul smell will also come out of these wounds. Not only in the bum, but these wounds can also spread up to the anus and rectum. All the lesions and wounds can make your dog’s bum look reddish.

Perianal Tumors

When tissues develop around the anal area, this increase in tissues can lead to the development of perianal tumors. Like any other tumors, tumors in this region can be of two types: benign, harmless, and malignant, which is harmful. 

Male dogs are more susceptible to the development of tumors. The lump developed around the anus can bring the skin out of the fur. So, you might notice discoloration around your dog’s bum because of this. 

Rectal Prolapse

Rectal prolapse is the condition in which more tissues develop in the rectum region. This excess tissue forms a lump and causes discoloration on and around the bum. We are going to discuss rectal prolapse in detail in the following section.

Why Is My Dogs Anus Turning Black

Why is My Dog’s Anus Turning Black?

It might be a symptom of rectal prolapse.

Well, now it is time to talk about why the anus of your dog is turning black. This is a severe problem and can indicate other serious health issues. Rectal prolapse, also known as anal prolapse, causes this darkening of the anus. 

Under this condition, the tissues in the rectum protrude out of them, and your dog can experience straining while performing renal activities such as pooping and peeing. This prolapse can be of two types:

Partial Prolapse

Partial prolapse is the condition in which only a tiny portion of the dog’s anus or rectum comes out only during peeing and pooping. After that, the tissues get back to their normal position.

Complete Prolapse

Both anal and rectal tissues will protrude out of the anus if your dog is suffering from complete prolapse. You can notice this all the time, unlike in partial prolapse, in which the tissues protrude out only during peeing and pooping. One of the other differences is that the tissues will not return inside the anus under any circumstances.  

In the beginning, the tissues coming out of the anus will look red, and the swelling will make the anus full of fluid. If the prolapse is not the partial type, then the condition will persist, and eventually, your dog will have to deal with the problem of complete prolapse. 

After complete prolapse, the tissues in the rectum and anus will start getting dry with time. Complete prolapse of the anus will make the tissue darker, and from the outside, it will look like the anus of your dog is turning dark blue or black. 

This primarily happens because blood flow stops in this region. This is extremely harmful to your dog and can eventually lead to the death of your pet. 

Why Is My Dogs Anus Turning Black


Rectal or anal prolapse might be causing this black coloration on your dog’s anus, but what causes this prolapse of tissues in a dog’s body? Well, the root causes behind this are:

  • Diarrhea will lead to strain while pooping.
  • Constipation will lead to problems in the digestive system of your dog.
  • Parasitic infections.
  • Inflammation of the intestinal tract is closely related to the renal system in a dog’s body.

Other than that straining while peeing because of obstruction in the urethral tract, enlargement of the prostate gland, dystocia, which is a condition seen in pregnant female dogs, defects in anus from birth, rectal polyps, and last but not the least development of tumors in the rectum and anus can be behind your dog’s anus turning more black with every passing day. 

Natural Change of Color

The cause that we are going to talk about now is not related to the dog’s health, but it can also make you think that the anus of your pet dog is turning black, and that is the change in the color of the fur of your dog. 

If the fur near the anus turns dark black which was less dark during birth, it can make you think like an owner that it is a severe health issue that your dog is dealing with. Honestly, there is nothing to worry about as this is entirely natural. 

Why is My Dog’s Butt Black?

Now, as you know, the root causes behind the change in color of your dog’s bum, alongside that in some cases, you might also notice black bums in your dog’s body. Anal prolapse or rectal prolapse infection that is causing a black-colored anus in your pet can also spread beyond the anus. 

When the infection spreads into the bum region, the lack of blood reaching that section due to the prolapse will make your dog’s butt look black. Other than that, if you do not clean your dog correctly and do not bathe them for a prolonged period, dirt will start accumulating in that region, and the butt of your dog will start looking dirty and black. 

Why Is My Dogs Anus Turning Black

Frequently Asked Questions

Why is my dog’s bottom turning black?

It could be due to hyperpigmentation if you don’t see any tissue hanging out.

The bottom part of a dog’s body means the tummy can change color and turn black. This darkening of skin color will become visible whenever more pigment accumulates in that particular region. 

It is known as hyperpigmentation. Hyperpigmentation changes the fur colour. Sometimes a dog’s bottom can also turn black when a dog is suffering from skin allergies, skin infections, and metabolic problems, which are often related to endocrine disorders.

What color should my dog’s anus be?

There is no specific color, it may be as per the dog’s natural color.

In natural conditions, a dog’s anus should look normal and brown. Fluid comes out from the anus almost all the time, and this fluid has a strong scent. 

Sometimes the color of this anal fluid can change, and this color change can also change the color of the anus. In this situation, abnormal colors of the anus can be seen.

Why is my anus turning black?

It might be a symptom of perianal hematoma.

The most common reason behind a person’s anus turning black is a perianal hematoma. If a person suffers from this, all the blood vessels around the anus will rupture. 

Ruptured blood vessels will disrupt the blood flow, and when blood clots in that area, the skin around the anus will turn bluish and then black.

Final Words

To identify whether your dog’s anus is turning black or not, you have to be very watchful. If you notice something like this in your dog’s body, don’t leave this untreated, as it can be a symptom of some of the fatal diseases seen in dogs. Take your pet dog to the nearest veterinary clinic for proper treatment. 

Thank you for reading: we hope we have answered your queries. You might also like to read about other problems in dogs such as: Why Does My Dog Poop Standing Up? And Does It Hurt A Dog To Poop After Being Spayed?