5 Causes of Constipation in Dogs

5 Causes of Constipation in Dogs

Does your dog strain when defecating? When he/she goes is it only a small amount? Does it come out hard or dry?

If that is the case, then your dog may be constipated. The process of defecation is an intricate process that involves involuntary actions of the intestines and voluntary action involving the muscles surrounding the rectum. If anything in this process is defective it can cause constipation. Constipation can be a primary health issue, but it is often a symptom of a more serious health issue.

Here Are Some Potential Causes of Constipation in Dogs:


If your dog has an unusual appetite for things other than dog food, constipation can be a potential problem. Common offenders include mulch, grass, hair, tree bark, bones, sticks, and pieces of rawhide. Since these things are not able to be digested, they are often passed in the feces. Often times they add bulk to the feces making it more difficult to pass through the intestines. Also the sharp edges of some of these objects can cause the feces to get stuck in the intestines.

Orthopedic Pain

If you watch your dog defecate, you will notice that the posture involves an arched back and hind limbs in a bent position. If there is pain in the back or the hips, they may be hesitant to defecate because of this pain. This potentially could lead to constipation. Back pain could be due to trauma or a bulging disc causing pressure on the spine. Hip pain could be due to arthritis, or hip fractures from a traumatic incident.

Perineal Hernia

There are a group of muscles surrounding the rectum that make up the anal sphincter. The sphincter helps with defecation with voluntary contractions that help expel feces from the rectum. In perineal hernia, these muscles undergo a progressive weakening for an unknown reason. Theories include influence of sex hormones in intact males, degenerative nerve disease, or a history of straining of these muscles.

This condition is more common in older, male, large breed dogs. In addition to straining, a swelling may be seen on either side of the rectum. The reason for this is when these muscles weaken, the rectal tissue bulges or herniates through them. This causes feces to be caught in the herniation instead of being expelled from the body. Often surgery is needed to correct this issue.

Rectal Tumors or Masses

Masses can sometimes develop inside of your dog’s bowel. If these masses are large enough they can cause an obstruction leading to constipation. These masses can often be palpated on rectal examinationby your veterinarian. Biopsies of rectal masses should be considered to determine if they are malignant or benign. Polyps are common benign tumors that may require surgical removal. Some common malignant masses include sarcomas, and lymphoma. A diagnosis via biopsy will help determine the best treatment for these type of tumors

Neurological Disease

As mentioned before, the process of defecation is an intricate process involving actions of the intestines and muscles surrounding the rectum. The spinal cord and the nerves supply these areas allowing for these functions to occur. If these structures are damaged for any reason whether it is due to trauma, degenerative disease, or a bulging discs, then the ability for your dog to defecate may be affected.

How Not to Deal With Constipation

Don’t self -medicate: As an owner you may be tempted treat your constipated dog with common home remedies such as canned pumpkin, mineral oil, and over the counter enemas.

Canned pumpkin: It can help in some cases of constipation, but there are some of the conditions mentioned where it would make things worse.

Mineral oil: This can be very risky to give your dog. There is a risk that the oil can get into the lungs causing a condition called aspiration pneumonia. This is often an irreversible form of inflammation of the lungs that can be deadly.

Over the counter enemas: These can be toxic to your dog, especially Fleet enemas. They can cause major electrolyte disturbances inside the body. These changes can lead to heart rhythm abnormalities, muscle tremors, seizures, and lethargy.


If you suspect constipation in your dog, it is best to contact your veterinarian to determine if the cause is primary or secondary before treating it yourself. A physical exam will help rule out some of the conditions mentioned in the article.

Additional diagnostics that your veterinarian may consider are x-rays of the abdomen, and lab work. Your veterinarian may decide to treat your pet by administering an enema, giving fluids, and sending home a stool softener. In extreme cases, your dog may need to be anesthetized and the feces will have to be manually removed from the bowels.

Dwight AlleyneDwight Alleyne, DVM

Dwight Alleyne, DVM is the author of the Animal Doctor Blog, a blog that provides veterinary information about cats and dogs through articles and product reviews. He has almost 20 years of animal experience with 10 years as a veterinary technician and more than 9 years as a veterinarian. He currently practices in Georgia at a small animal practice where he provides veterinary services through surgeries and medical consultations. When he is not working, Dr. Alleyne enjoys spending time with his wife, daughter, and 7 year old cat named Queen.

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