Why Is My Dog Bleeding From Its Anus? - Causes

By Ameera Mills. Updated: May 16, 2021
Why Is My Dog Bleeding From Its Anus? - Causes

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Rectal bleeding in dogs, wherever it occurs, is always cause for alarm among pet guardians. A dog may bleed from its rear end due to many different reasons. The origin of the blood, however, can differ. Therefore, if your dog is bleeding from its rectum it is incredibly important that you go to a veterinarian as soon as possible. A veterinarian will be able to make a correct diagnosis and treat the symptoms accordingly.

However, for more information, we here at AnimalWised wanted to explain some of the possible reasons why your dog is bleeding from its anus. We will be covering common causes of rectal bleeding, differentiating where the blood is really coming from and what you can do about it.

You may also be interested in: My Dog Is Bleeding From Their Mouth

There are different reasons why a dog may be bleeding from the rectum, each related to different a source within the dog's body. We are going to discuss the most common causes for anal bleeding in dogs, which are:

  1. Hemorrhage in the digestive system
  2. Constipation
  3. Infection of the anal glands
  4. Other causes (rectal bleeding along with vomiting)

1. Dog rectal bleeding - Hemorrhage in the digestive system

The digestive system of a dog starts at its mouth, continues down the esophagus to the stomach, small intensive, large intestine and ends at its anus. If there is a hemorrhage in any part of this system, including the nasal cavity or lungs, the blood will be expelled through the dog’s anus.

Therefore, the cause of bleeding in a dog's rear end can originate from several different areas within their body. This is why a diagnosis is so incredibly important. In order to proceed with a diagnosis, it is important to check the texture and presentation of the stool itself. Blood in a dog’s feces is medically classified into two types: hematochezia or melena.

  • Hematochezia causes the expulsion of fresh, red and bright blood that can appear in normal stools or as bloody diarrhea. This blood in the dog's stool usually comes from the colon, rectum or anus.
  • Melena causes a dog’s feces to appear black or tarry. This color suggests that the blood is coming from the upper intestinal tract.

In order to diagnose dog rectal bleeding effectively, one also needs to notice whether the blood is mixed with the feces, or on the outside of the feces, and what color the blood is. These all function as signs which can help you work out the cause of your dog bleeding from its bottom.


Why Is My Dog Bleeding From Its Anus? - Causes - 1. Dog rectal bleeding - Hemorrhage in the digestive system

2. Rectal bleeding in dogs - Constipation

Is your dog bleeding from its rear end? Constipation may be one of the main causes. You can tell whether your dog is constipated by noticing that the dog does not defecate at all, or does so in a small amounts, with obvious difficulty. The effort it takes the dog to defecate can often cause bleeding from its rectum.

Constipation in dogs can be caused my many different things, one being dehydration. Dehydration in dogs can can cause a dog’s stool to dry up, which will naturally make it difficult to expel. This can cause slight rectal bleeding. For more, take a look at our article on signs my dog is dehydrated.

If a dog swallows bones, tissues and other substances which are difficult or impossible to digest, this can cause bleeding in the dog’s anus. Some medications can also result in constipation as a side effect. In addition, there many diseases which can cause constipation. These include diseases such as hypothyroidism and specific digestive diseases.

If you observe rectal bleeding in dogs, pain when defecating and/or painful efforts to defecate, we suggest visiting your veterinarian as soon as possible. If your dog is in fact suffering from constipation, a doctor will be able to treat this effectively. You can also prevent constipation in your dog by following these tips:

  • Provide correct diet and hydration that facilitates the intestinal transit.
  • Avoid feeding them bones.
  • Schedule regular veterinary reviews that can detect diseases in time.
  • Maintain a safe environment to prevent the ingestion of foreign bodies.
  • Never medicate a dog without veterinary supervision.
  • Give your dog sufficient opportunity to defecate and exercise.
Why Is My Dog Bleeding From Its Anus? - Causes - 2. Rectal bleeding in dogs - Constipation

3. Canine rectal bleeding - Infection of the anal glands

A dog has two two glands or sacs located on both sides of the anus. When feces are expelled, it can exert pressure on these glands. These glands then empty a liquid to aid with lubrication. Sometimes, however, the anal glands can become infected, which may explain why a dog starts bleeding from the rectum. In these cases, the dog will feel pain and a yellow or bloody discharge will be released. A dog suffering from this problem will also most likely rub or drag its bum on the ground or lick the infected area. A veterinarian will be able to drain the glands and administer appropriate antibiotics to cure any infection[1].

Often, if the inflammation targets only one gland, it could mean that the dog is suffering from an abscess. This abscess can break the skin, producing a perianal fistula from which a foul-smelling liquid will emerge. If this is the case, it is very important to go to the veterinarian as soon as possible, as in severe cases an abscess may require surgery. Disinfection and the administration of antibiotics will also be necessary to treat abscesses[2].

Why Is My Dog Bleeding From Its Anus? - Causes - 3. Canine rectal bleeding - Infection of the anal glands

My dog is bleeding from the rectum and throwing up

If you notice your dog bleeding from its rectum and vomiting, then it is critical to take them to veterinarian as soon as possible. Rectal bleeding in dogs partnered with vomiting can be a sign of various conditions or diseases, such as:

  • Ulcers in dogs: these are lesions in the mucous membrane of the digestive system, often caused by the use of medications such as corticosteroids, but also by diseases such as kidney or liver failure. They can cause vomiting, anemia, thinning as well as anal bleeding.
  • Canine parvovirus: this condition mainly affects puppies and is characterized by the presence of vomiting and bloody diarrhea. It is a very serious and contagious, and vaccination is essential to prevent it.
  • Dog poisoning: the ingestion of some toxins can cause symptoms such as rectal bleeding in dogs and/or vomiting blood. Immediate veterinary assistance is required as dog poisoning can be fatal.
  • Heat stroke in dogs: an excessive rise in the body temperature of a dog produces, among other symptoms, vomiting and diarrhea with blood in the stool. This can happen when, for example, a dog is left inside a closed car during the hottest hours of the day. Heat stroke should be treated immediately as it can result in death.
  • Renal insufficiency in dogs: Kidney failure in dogs can also cause vomiting and the presence of blood in feces, due to causes such as gastrointestinal hemorrhages. These hemorrhages need to be stabilized by appropriate veterinarian treatment. For more, take a look at renal failure in dogs.

This article is purely informative. AnimalWised does not have the authority to prescribe any veterinary treatment or create a diagnosis. We invite you to take your pet to the veterinarian if they are suffering from any condition or pain.

If you want to read similar articles to Why Is My Dog Bleeding From Its Anus? - Causes, we recommend you visit our Other health problems category.

  1. Jung, Y., et al. (2016). Diagnostic imaging features of normal anal sacs in dogs and cats. Journal of Veterinary Science, 17(3), 331-335.
  2. Rannou, B. and Bédard, C. (2009). Rectal plasmacytoma with intracellular hemosiderin in a dog. Veterinary Pathology, 46(6), 1181-4.

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My 12 year old hound rescue had sarcoma near the rectum a year ago. After surgery, she has been fine. She started with loose stool surrounded by blood for several days. Her activity and eating were fine. Vet put her on probiotics and antibiotics. A protrusion did appear on her spleen on an x-ray. Poop almost immediately became normal. Any ideas as to what we're dealing with? Thank you!
William Lind
Good read. I'm convinced my Cane Corso at a box of tooth picks and punctured her upper intestine, or any where else along the tract. I came home to her so weak she couldn't lift her head. Puddles of blood everywhere. She held on till I got home from work. I don't think a vet could have done much by that point. Have large dogs? Keep counter tops clean!!!
Administrador AnimalWised
Hi William

We are so sorry to read your story, but we appreciate the advice for other guardians. It is very important and we hope it helps others avoid accidents like this one!
Robert Anderson
My girlfriend's dog has ulcers and has blood in stool. My question is: will omeprazole 20mg be helpful or harmful for him. He is slightly over weight, 8 yrs old.
Princy L. Fernandes
I need your guidance, plz. My dog, that night, he was sitting with his ears down, I sat next to him and saw a patch of blood on the floor. So I checked where he bled and it was from a part above his anus. Whenever we call him, he doesn't come at all. When we try to search him everywhere, he just digs a hole and sits there in the sand in our backyard. It's like his resisting us. That night, the wound had small ants running over it and it had a foul smell. Also we didnt bathe him for fee weeks cause the next day he would be covered in muddy water. I thing, this night have triggered his infection, o guess? For the past two days, he hasn't eaten his food. He just keeps on drinking water. It has been just 1yr and 3 months that we bought him. My dog will be okay right? I'm scared. Plz tell me what's wrong with him. PLEASE~~
Administrador AnimalWised

We are so sorry to hear about your dog. When a dog stops eating, it implies the symptoms are relating to a potentially serious condition. However, we are not able to give you any type of diagnosis. This can only come from a qualified veterinarian. If it is an infection, they will be able to prescribe the correct treatment (likely in the form of antibiotics). If not, they will be best placed to diagnose the problem and provide the right course of treatment.
our dog did this and they needed anual glands cleaned or squeezed and tear the skin if not done - best for vet to do. never knew - some dogs need anual glands clean or squeezed regularly - not all just some . maybe dogs proably - wheather asking vet to check them !!! better then surgery - thought they had cancer but no no thank goodness - might ask vet
Obviously late posting to this question, and certainly hope everything worked out... BUT I had to comment (esp for others that may have similar situation)... bc I am just soo incredibly HORRIFIED to even read this! #1 answer to this & other similar questions - TAKE HIM TO A VET ASAP!!! My guess is that it could have been anal compaction that subsequently got a very serious, secondary infection.... BUT even thinking of the type of conditions this dog clearly is living in, probably turns my stomach even more. Also, WHY on earth would somebody NOT automatically think of taking a seriously bleeding dog ro a VET IMMEDIATELY either? Would you treat your children in the same manner too?
Just my own belief, BUT when you take ANY ANIMAL into your care, YOU are fully responsible for the WELL BEING, QUALITY OF LIFE & EVERYTHING ELSE that has ANYTHING to do with that animal... and yes even treating them just as well as you would for your own children!
I also STRONGLY believe that if you can't keep that animal to live in the same living conditions as yourself, you really should have NO business owning that dog/animal in the 1st place. It really boils my blood to see people (some I would even refer to as 'collectors') acquire dog after dog, just to throw them into the backyard with little to no real interaction - except for filling up a bowl with water and food (if they remember). Nevermind those that not only do that, but make sure they're also stuck living their entire lives at the end of a chain to boot! Such treatment (and/or lack of = NEGLECT! ) just absolutely turns my stomach... and to be honest, FINDING ANTS CRAWLING ALL OVER your CLEARLY SUFFERING DOG - tells me that you're most likely no better than what I just described. I could be wrong, but my gut tells me that I'm not too far off.
IF YOU DON'T HAVE THE TIME, INTEREST, MONEY OR ABILITY TO PROVIDE FOR THAT DOG - WHICH INCLUDES REGULAR VET VISITS (& ESP EMERGENY VET CARE)! You really NEED to find that dog ANOTHER HOME that will actually LOVE, GIVE ATTENTION &PROVIDE all the basic necessities- including treating it as part of the family! Dogs are PACK animals & very much need regular attention & interaction direct interaction with its family members (it sees as pack members). ISOLATION & esp being CHAINED up away from everyone, is JUST ABOUT THE MOST CRUEL thing you can do to any dog! It's JUST AS MUCH CRUEL as not keeping it properly fed, at the least daily fresh water in REGULARLY CLEANED bowls! Anyone that uses the EXCUSE that it can't be kept inside bc if its behavior, also should NEVER OWN A DOG either! If you don't have the time to also TRAIN it (an absolute necessity for EVERY DOG from puppyhood and thruout its life) to be taught/ know HOW to act, interact and behave - you don't deserve the priviledge of owning a dog - period! Go get yourself a goldfish instead....
Rebecca Hauck
My older puppy has bled from his anus when he has worms. I know he's had roundworms and a tapeworm but I suspect the bleeding came from hookworms. After treatment for all types of worms, his bleeding stops. Then months down the road when he has more worms, his behind bleeds again until treatment.
Administrador AnimalWised
Hi Rebecca,

Is your puppy being dewormed properly or is it exposed to other dogs or places which have worm infestations?
Catherine Tucker
My dog was bleeding from his nose and butt. I am devastated due to the fact I had to put him down. I am still confused over the fact this happened in less than 24 hours. I have no idea what he was dying from. Can you give me some illnesses that would have resulted in this fast lose of life.
I have an Aussie Shepard she is over 14 years old and is sick don't know what's wrong with her she is bleeding from her bottom don't have any money to take her to the Vet to see if she has to be put down I don't want her to suffer anymore want do I do about help with her don't even have money to put her to sleep and have her cremated.
Administrador AnimalWised
Hi Terry,

If you don't have the money to take your dog to the vet and you think they are in pain or near the end of their life, you should get in ouch with your local shelter. Even if they cannot do it themselves, they should be able to provide more information about what services are available in your local area. We are sorry to hear about your friend. Even though this is an incredibly sad situation, it sounds like she has had a long life with a caring person and that is a lot. Good luck!
We recently got a new 13 week old puppy. Two days after we got him our seven-year-old Yorky did not want to eat and he started bleeding from his rectum. Other than that he is not acting abnormal in anyway except the bleeding
Tonya Akins
Babygirl my 11 year old lab has had blood in her stools for the past two days.. She is also very swollen down from the anus ..she's not in heat ..and she's in pain .. She healthy otherwise and is drinking and eating .. What could this be .. Plz let me no
Administrador AnimalWised
Hi Tonya,

Our article suggests the possible reasons why there may be blood in your dog's school, but it is only informative and cannot replace a medical diagnosis. This will take a physical examination along with other tests. Please take them to the vet if you see such symptoms as they will be best able to provide diagnosis and treatment options.
geraldine a johnson
is there anything over the counter we can give our dog for this anal bleeding!
Administrador AnimalWised
Hi Geraldine,

If your dog has anal bleeding, it could be the symptom of many different potential causes. Only a vet will be able to diagnose the problem. There could be something over the counter which will help, but you could also be avoiding proper treatment which can seriously threaten the health of the animal.
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Why Is My Dog Bleeding From Its Anus? - Causes

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