My Dog Hasn't Pooed: Causes of Constipation in Dogs

An occasional missed bowel movement is not usually cause for concern, but a dog straining to defecate, passing very hard or small stools, or not pooing for more than 48 hours needs attention. Constipation has several causes, most of which are treatable, but some indicate a more serious underlying problem.

Is This an Emergency?

Go to a vet or emergency clinic immediately if your dog:

• Is straining and crying or showing signs of severe pain in the abdomen
• Has a swollen or hard abdomen alongside the inability to defecate
• Has not defecated for more than 72 hours
• Is also vomiting and appears to be in pain (possible obstruction)
• Has a known tendency to swallow foreign objects

Call your vet the same day if:

• Your dog has not passed a stool for more than 48 hours
• Your dog is straining repeatedly but producing little or nothing
• You can see blood in or around the stool, or on the fur around the back end
• An older male dog is struggling to defecate (possible prostate enlargement)

Wait and monitor for 24 to 48 hours if:

• Your dog passed a stool within the last 24 hours and is otherwise well
• There has been a change in diet, exercise level, or routine

What Causes Constipation in Dogs?

Dehydration

Insufficient water intake causes the colon to draw more water from the stool, making it hard and difficult to pass. Always ensure fresh water is freely available.

Dietary causes

A diet low in fibre, or a recent dietary change, can alter stool consistency. Dogs that have swallowed hair, bone fragments, or grass may develop constipation as this material creates a firm plug.

Ingested foreign material

Bones, hair, grass, and other indigestible material can form a blockage in the colon. This is a common cause of constipation in dogs that groom excessively or are given recreational bones.

Reduced exercise

Exercise stimulates bowel motility. A dog that has been less active than usual due to illness, injury, or very cold weather may become temporarily constipated.

Prostate enlargement

In older, unneutered male dogs, an enlarged prostate can compress the rectum and make defecation difficult or painful. Neutering and/or medication can address this.

Megacolon

A permanently enlarged and weakened colon that loses the ability to move faecal material normally. More common in cats but does occur in dogs. Requires long-term management.

Neurological causes

Spinal cord problems, particularly in breeds predisposed to intervertebral disc disease (IVDD), can affect the nerve supply to the bowel and cause constipation or inability to defecate.

Which Breeds Are More Prone to Constipation?

• Dachshund, French Bulldog, Pug: IVDD can affect nerve supply to the bowel
• Labrador Retriever: Prone to ingesting foreign material that causes faecal impaction
• Unneutered male dogs of any breed: Prostate enlargement is a common cause in middle-aged to older dogs

What Will the Vet Do?

Your vet will palpate the abdomen to assess the amount and consistency of faecal material present and examine the rectum. They may recommend:

• Enema under sedation to clear the impaction
• X-rays to assess the degree of constipation and look for foreign material or abnormality
• Blood tests if a systemic cause such as kidney disease or hypothyroidism is suspected

How to Help Your Dog at Home

For mild, short-term constipation in an otherwise well dog:

• Ensure fresh water is always available and encourage drinking
• Increase exercise to stimulate bowel motility
• Add a small amount of plain, canned pumpkin (not pie filling) to food as a natural fibre source
• Do not give human laxatives, enemas, or stool softeners without veterinary guidance, as some are harmful to dogs