Constipation In Dogs: Common Causes and Symptoms

A constipated dog is not a happy dog. Find out the main causes and symptoms from our resident vet, Dr Andrew McKay.

Causes and Symptoms of Dog Constipation

What is constipation in dogs?

Constipation in dogs is all too common, and unpleasant for your pet and a worry for you as a dog owner. So what it is?

A dog's waste is full of water and electrolytes as it moves through their intestines to the colon by peristalsis (involuntary contraction & relaxation of muscles in the gut wall). Water and many of the electrolytes are absorbed by the dog in the colon and the waste is removed as feces.

If this process becomes slow or impaired, the colon will keep absorbing water and the stool will become harder, drier, and possibly compacted leading to constipation in your dog.

Constipation is the infrequent or difficult passage of faeces, where a dog just can’t pass a normal stool on a regular basis. 

The key is to fix constipation before it leads to obstipation, a severe form of constipation where the faeces in the dog's colon become drier, harder & more compacted preventing the dog being able to pass it at all. Once obstipation develops it’s important to seek veterinary advice immediately.

Constipation can occur for a number of reasons

1. Your dog eats an undigestible object

The most common cause of constipation in dogs is eating undigestible substances such as bones, garbage, plastic toys, which is common, especially in younger dogs. These foreign materials can block the gastrointestinal tract preventing the normal passage of food and waste.


My dog has constipation what do I do?

Eating garbage is a common reason for dog constipation.


2. Dogs with long hair are more susceptible to constipation

Dogs with long hair or those that lick or groom themselves excessively are also at risk at becoming constipated as they ingest hair that mixes with faeces which can clog up your dog's gut.

3. Dehydration

Dehydrated dogs are more predisposed to constipation as more moisture is absorbed from their food in the colon leaving dry hard faeces. Always make sure your dog has access to fresh, clean water.

Avoid constipation in your dog by providing clean fresh water

Provide clean fresh water to avoid constipation in your dog.

4. Lack of exercise

Exercise stimulates the colon which encourages the passage of waste to move through. Exercising outside provides an opportunity for dogs to keep themselves more regular. Old dogs are more likely to become constipated given they aren’t exercising as much later in life. They are also more likely to suffer from osteoarthritis in the lower spine & hips which can make it painful for them to squat to defecate. Old dogs are also more likely to have kidney disease that can lead to them being dehydrated and therefore increasing the risk of constipation.

5. Poor diet

Dogs with poor diets are more likely to get constipated. Be sure to feed your dog a complete and balanced diet containing all the essential nutrients including enough fibre.

Less common causes of dog constipation

  1. Hypothyroidism - underactive thyroid gland
  2. Enlarged prostate partially obstructing the colon
  3. Megacolon - enlarged colon with reduced or no peristaltic activity so unable to transport fecal material
  4. Spinal injury or neurological diseases can prevent peristaltic movement of the gut
  5. Certain medications (antihistamines, diuretics, narcotic pain relief) can reduce gut mobility
  6. Surgery or anesthesia effects 
  7. Stress, anxiety, fear or other behavioural conditions.
  8. Tumors or masses in the colon or rectum
  9. Pelvic injuries or abnormalities

Symptoms of Dog Constipation

Dogs produce faeces (defecate) at least once a day and many have bowel movements that correspond to the number of meals eaten per day. 

By definition, the main symptom of constipation is a lack of defecation. Other signs to watch out for include:

  • Straining to defecate without producing much.
  • Pain while trying to defecate. 
  • Very dry hard pellet-like stools. 
  • Passing small amounts of liquid poo or even blood that can squeeze past the dry compacted poo in the colon. 

In more advanced cases of constipation, dogs will lose their appetite, their abdomen may become distended and painful to touch, they have a lack of energy and can start vomiting. It is important to seek urgent veterinary care once you see these signs.

Read about how to Treat Constipation at home HERE

The information in this article was written by Heartly's Veterinarian, Dr Andrew McKay, BVSc, University of Melbourne, 2000. Vet Registration No: V3985