Painful Defecation in Dogs: Causes and Treatment

Medically Reviewed by Amy Flowers, DVM on May 28, 2023
4 min read

Common causes of painful defecation in dogs include:


Many things can lead to diarrhea in dogs, including inflammatory bowel disease, medications, allergies, food poisoning, parasites, a change in diet, and gastrointestinal infections.

Symptoms of diarrhea are pretty easy to spot: loose, liquid, or frequent stools. As with so many conditions, treatment depends on the cause of the diarrhea and may include dietary changes, fluid therapy to prevent dehydration, and occasionally antibiotics if an infection is identified.

Get your dog vet care right away if they have more than one episode of diarrhea, is lethargic, has a fever, blood in the stool, or black, tarry stool.


Like diarrhea, constipation in dogs can be caused by a wide range of things, including certain drugs, intestinal obstruction, enlarged prostate or lymph nodes, dehydration, tumors, and neuromuscular problems.

Signs of constipation include: straining to defecate; firm, dry or ribbon-like feces; depression; lethargy; vomiting; loss of appetite; and stomach pain. Treating constipation depends on its cause, though for mild constipation a high-fiber diet, plenty of water, and laxatives as prescribed by your vet may be all the treatment needed.

If the constipation is serious, manual removal of impacted feces under general anesthesia may be necessary.

Foreign Object

Some dogs have a habit of eating inedible objects like pebbles, bones, or used food wrappers, for example. If your dog does this, it could be the source of your canine companion's painful defecation.

Treatment will depend on the object ingested, the dog’s symptoms, and a physical exam, so always consult your vet if your dog has swallowed something inedible.

Consider it an emergency if your dog has swallowed string or something with string attached. If the item lodges in one spot, the string can act like a saw, perforating the intestine and leading to life-threatening peritonitis -- inflammation of the abdominal lining.

Acute hemorrhagic diarrhea syndrome

Acute hemorrhagic diarrhea syndrome or AHDS (formerly hemorrhagic gastroenteritis is distinguished by a sudden onset of vomit and bloody diarrhea in a previously healthy dog. Take your dog to the vet immediately if they show these symptoms as untreated AHDS can be fatal.

No one knows what causes the disorder, but it may begin with infection from an intestinal bacterium called Clostridium perfringens Type A Some dogs are more inclined to get the condition, including toy poodles, miniature schnauzers, Pekingese, Shetland sheepdogs, Yorkshire terriers, and King Charles spaniels.

Along with bloody diarrhea and vomiting, signs of hemorrhagic gastroenteritis in dogs include loss of appetite and depression. Treatment for this disorder -- which is not thought to be contagious -- includes fluids, diet changes, and possible antibiotics.

Anal Sac Inflammation

Anal sacs contain a fatty, smelly substance that your dog uses to communicate with other canines. Located under the skin on either side of your dog's anus at about the four o'clock and eight o'clock positions, anal sacs can sometimes become blocked, inflamed, or abscessed, making defecation painful.

Symptoms of anal sac problems include your dog dragging their bottom along the ground, as well as licking and chewing at the area. Swelling may be noted on one or both sides of the anus as well. Treatment varies depending on what's causing the problem but may include expressing the sacs, flushing them with an antiseptic or antibiotic, or lancing the sac, sometimes under general anesthesia.

Enlarged Prostate

Painful defecation in dogs can also be the result of an enlarged prostate pressing against your dog's rectum. Several things can cause a prostate to become enlarged, including a tumor, infection, or hormones if the dog is not neutered.

Straining to defecate and blood in the urine are signs of an enlarged prostate; if infection is the cause of the enlargement, your dog may also urinate more or drink more water. Treating an enlarged prostate depends on what's causing it, but may include surgery, neutering, or a course of antibiotics.

Stool samples are a big part of diagnosing the cause of your dog's painful defecation. When collecting a stool sample for your vet:

  • Remember that fresher is better; a stool sample less than 24 hours old is ideal.
  • Collect at least a teaspoon of stool. Don't worry if there's a little debris like grass or leaves attached.
  • Keep the stool refrigerated, but not frozen. If you or your vet suspects your dog has parasites, don't refrigerate the sample.

Because so many things can cause constipation, diarrhea, or other symptoms that lead to painful defecation for your dog, it can be hard to prevent the problem. Your vet can make suggestions based on your dog's problems.

One way you can help your pet avoid bowel-related distress is by making sure frequent microscopic fecal checks are conducted.