Constipation in dogs

“Constipation” is defined as infrequent and difficult passing of dry, hard stools. It can evolve into “obstipation”, when the animal is unable to eliminate too hard stool. Constipation in dogs is also a common disease.

The term “tenesmus” refers to painful and ineffective exertion during bowel movements. The term “dyschezia” refers to a painful or difficult evacuation of stool from the rectum. Therefore, Dyschezia encounters in anal or perianal attacks and can lead, in a second step, to constipation or even obstruction.

The last part of the digestive tract consists of the colon which has a role of reabsorption of water and minerals as well as a role of storing stool. Colonic contractions move stools towards the anus for evacuation. These contractions make possible thanks to the innervation of the autonomic nervous system.

During defecation there is a contraction of the colon and a relaxation of the anal sphincter: the animal has its back arched, it contracts its diaphragm and its abdominal muscles in order to increase the intra-abdominal pressure.

Causes of constipation

Several diseases can be the cause of constipation in dogs, that is to say, the cause of dry, hard and difficult to eliminate stools. Indeed, as soon as the residence time of the stool in the colon increases, the reabsorption of water is greater and the stools are drier.

It exists :

  • Neurological dysfunctions of the spinal cord (malformation, cauda equina syndrome, etc.) or peripheral nerves causing a defect in colon contraction.
  • A mechanical obstruction that can also prevent the progression of stool through the colon. She may be :
    • internal, related to partial or total occlusion in the lumen of the digestive tract (foreign bodies such as bones, stenosis, tumor, polyps);
    • internal linked to an abnormal storage “pocket” within the colon or rectum (diverticulum, perineal hernia, etc.)
    • external and cause compression of the colon (prostatic involvement in the male, vaginal or uterine involvement in the female, bone damage in the pelvis – fracture, tumor, etc.).
  • Certain general diseases (renal failure, certain tumors) causing water imbalances (dehydration) or minerals (hypokalaemia, hypercalcemia).
  • Hormonal imbalances (hypothyroidism,…), a state of obesity or inactivity which are contributing factors.
  • Pathologies of the perianal tissues (abscesses of the anal glands, anal fistulas, etc.), in long-haired breeds, soiled hair in the anal region (acting as a “plug”) or osteoarthritis which can cause pain associated with dyschezia and secondarily lead to constipation.
  • A diet low in fiber or high in bone as well as a reduced intake of water.

Symptoms of constipation

During constipation in dogs, the animal gets into position for a long time or repeatedly, and manages to eliminate hard, dry stools. Sometimes the stool may tinge with blood in nature; anal prolapse (eversion of the anus) can sometimes occur.

In the most serious cases, no stool can eliminate.

Depending on the underlying cause, it is possible to highlight distension of the abdomen, dehydration, generalized weakness, swelling, bleeding in the perianal region or locomotor disorders of the hind legs.


The diagnosis of dog constipation and the cause of the latter requires, first of all, a precise collection of the animal’s history (age, breed, pathological history, treatments, etc.).

Secondly, a meticulous clinical examination is essential: examination of the anal and perianal regions (raising the tail, rectal examination, etc.), abdominal palpation as well as a complete neurological and orthopedic examination are essential. In some cases, sedation may be necessary in order to properly examine your animal.

Depending on the results of the clinical examination, certain additional examinations may be performed:

  • X-ray (abdominal, pelvis, spine)
  • Abdominal ultrasound
  • CT scan or MRI of the spinal cord
  • Blood tests
  • Colonoscopy
Constipation in dogs

Treatment of constipation in dogs

The management will depend on the cause of your dog’s constipation.

During severe constipation, it is sometimes essential to perform a colonic enema under anesthesia and resuscitate your animal (rehydration, pain management, etc.): these enemas can be repeated several times a day or over several consecutive days .

Symptomatic medical management may be sufficient to manage transient constipation: for this, your veterinarian will prescribe digestive lubricants and / or laxatives to your animal to be administered orally or intra-rectally.

A dietary change to a high fiber diet can sometimes be essential.

A specific treatment of the cause is recommended: it can be surgical, medical or mixed. Here are a few examples:

  • Surgical: castration during hyperplasia of the prostate, excision of an intrarectal tumor, correction of the perineal hernia, reduction of a pelvic fracture, etc.
  • Medical: hormonal supplementation in hypothyroidism, antibiotic therapy in anal gland abscess, hair clipping in the anal region, etc.
  • Medical +/- surgical: anal fistulas, colectomy and adapted diet during megacolon

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The prognosis is very variable depending on the cause. The treatment is sometimes definitive and makes it possible to cure the animal. But, in certain other cases, the management does not make it possible to control the symptoms satisfactorily.


The demonstration of constipation in your dog requires consulting your veterinarian. The latter will implement a rigorous diagnostic process to find the cause of these symptoms. Appropriate therapeutic care will thus be put in place.