Dog constipation can have a variety of causes and may require veterinary intervention. Integrative veterinarian Dr. Julie Buzby discusses 14 causes of constipation. Plus, she explains the symptoms, diagnosis, treatment, and prevention of constipation so you know what to expect and when you need to take a potentially constipated dog to the vet.
Between the bloated feeling, abdominal cramps, and frequent urge to defecate, constipation can be an uncomfortable condition for people—and dogs, too! Dogs can get constipated, but for them, the solution isn’t always as simple as upping their fiber intake, going on a walk, or drinking more water. Sometimes they need veterinary attention.
What is constipation in dogs?
Constipation is the accumulation of dry, hard stool in the colon and rectum, resulting in difficult or less frequent defecation. Chronic constipation may also lead to obstipation, a more severe form of constipation where the dog has a dry mass of stool in the colon that he or she cannot pass. As a result of obstipation or repeated constipation, the dog also may develop chronic distension of the colon (megacolon), which further contributes to issues passing stool.
How does constipation occur?
In short, constipation happens when a condition or situation interferes with the dog’s ability to defecate. There are a variety of places in the process of making, storing, and passing the stool where things can go wrong.
In a normal dog, the beginning parts of the colon are responsible for absorbing water and electrolytes from the ingesta (food and water in the digestive tract). The leftover undigested material and some other bodily waste products become feces. They are stored in the last parts of the colon until it is time to defecate.
A collection of nerves is responsible for moving the ingesta/feces along the length of the colon and sensing the presence of feces in the rectum. They also keep the sphincters closed until it is time for a bowel movement and then help evacuate the stool.
The stool may remain in the colon longer than normal if:
- It contains foreign material that makes it get stuck
- The colon is narrower than it should be
- The stool is drier or firmer than normal (usually due to less fluid in it)
- The sensory or motor nerves aren’t functioning normally
- The dog is reluctant to initiate defecation
When the dog doesn’t defecate, the stool becomes very dry and can damage the lining of the colon. In response, the lining of the colon pulls fluid into the area around the too-firm feces. This can lead to fluid loss and dehydration. Further, the body may reabsorb the toxic waste products that originally accumulated in the fecal matter, and the dog may begin to become systemically ill.
Why is my dog constipated? 14 causes
There are numerous causes of constipation in dogs, including:
1. Dehydration
Kidney failure in dogs, prolonged vomiting, and other causes of dehydration in dogs can lead to constipation. Dogs who don’t have enough fluid in the body in general will also have less fluid in the feces. This makes the stool drier, which can lead to constipation.
2. Ingesting inedible materials
Eating rocks, sticks, dirt, pieces of toys, bones, hair, and other items can lead to physical blockage of the colon or very slow passage through the colon. As the stool sits there, it will continue to dry out, worsening the constipation.
Or in some cases, the foreign object may lodge somewhere in the small intestines instead. Dogs with an upper GI obstruction will be vomiting and may not have much stool coming through. But they aren’t truly constipated.
3. Neurologic problems
Dogs with malformed or damaged spinal cords can develop constipation as a result of fewer colonic contractions. This is especially likely if the problem is at the level of the lower back and tail.
4. Muscle and joint pain or weakness
Muscle and joint pain may make dogs reluctant to have a bowel movement. Plus, weakness can make it physically difficult for the dog to posture to defecate and hold that position for a sufficient amount of time. As a result, osteoarthritis in dogs and other similar conditions can lead to constipation.
5. Disorders of the anal or pelvic region
Conditions such as anal gland issues in dogs (abscesses or rupture), perianal fistulas, and hip fractures can make defecation painful. Thus, the dog may pass stool less frequently.
6. Electrolyte disturbances
Low potassium, low magnesium, and abnormal calcium levels (both low calcium and high calcium in dogs) can lower smooth muscle contractions of the colon. This can slow down the movement of ingesta or stool, leading to constipation.
7. Endocrine disorders
Diseases impacting the endocrine system, such as diabetes in dogs and hypothyroidism in dogs, may potentially lead to constipation as well.
8. Medications
Some medications may slow colonic contractions, including opioids, antihistamines, and aluminum hydroxide. Plus, diuretics can affect electrolyte levels and cause dehydration. And iron supplements draw water out of the colon. All of these actions can lead to constipation.
9. Internal obstruction of the colon or rectum
If the dog has a polyp, tumor, stricture, or other abnormality inside the colon and/or rectum that causes it to get narrower, this can make it difficult to get stool past that area. As a result, the dog may become constipated.
10. External obstructions of the rectum
Anatomic changes like an enlarged prostate in dogs, anal tumors, pelvic fractures, and perineal hernias can compress the colon or rectum from the outside. This makes it challenging for stool to get through the narrowed area.
Additionally, large mats of feces and/or fur can also cover the anal opening, leading to stool retention. This is called pseudocoprostasis.
11. Obesity
Obese dogs have extra adipose (fatty) tissue in the abdomen, which can compress the intestines. And they tend to have alterations in the bacterial population of the gut. To make matters worse, obesity can also cause hormonal imbalances that further impact gut health in dogs. The combination of these factors may lead to constipation.
12. Stress and anxiety
Anxiety can cause gastrointestinal disturbances due to the effect of “fight or flight” hormones that slow digestion. This may lead to constipation. (However, stress colitis in dogs, which usually causes diarrhea, is also possible in high-anxiety dogs.)
13. Lack of exercise
Physical activity can stimulate intestinal muscles and improve the flow of blood to the digestive tract. Thus, dogs who are less active, such as senior dogs with arthritis, may be prone to suffering from constipation due to inactivity.
14. Dietary factors
The amount of fiber in a dog’s diet can impact their stool quality, so dogs receiving too much or too little fiber could become constipated. Additionally, rapidly changing from one food to another can throw off the gut, leading to either constipation or, more frequently, diarrhea.
What are the symptoms of constipation in dogs?
Dogs may exhibit a variety of symptoms depending on how long the constipation has been going on, how severe it is, and what initially caused it. At first, you may just notice that you aren’t picking up as many piles of poop. However, as it goes on longer, the dog may start showing more abnormal behaviors or acting systemically ill.
Symptoms more directly related to constipation
Sometimes dog constipation symptoms are more directly related to the difficulty he or she is having in passing feces. They include:
- Straining to defecate (tenesmus): You may notice that your pup is squatting frequently. Or he or she might remain in a “pooping posture” for longer than normal.
- Acting like it is painful to defecate (dyschezia): Whining, yelping, or turning around and looking at the hind end while posturing may all point to painful pooping.
- Circling excessively: Your dog may do the “potty dance” for a bit, squat, then get up and do the same thing again somewhere else.
- Scooting and licking: Due to soreness or discomfort in the area, the dog may scoot the bottom on the ground, or you may notice the dog licking the base of the tail.
- Tense, painful abdomen: Abdominal cramps and the buildup of fecal material can cause the dog’s belly to hurt. Sometimes the dog may stand in a play bow or stretched out position.
- Passing small amounts of stool: The dog may get out small, dry “rabbit pellets.” Or in some cases, the dog squeezes out a small amount of liquid feces around the firm, dry fecal material. This is not diarrhea, although it may look like it.
- Less frequent bowel movements: The average adult dog usually defecates 1-3 times a day, while puppies may pass feces five times a day. Less than that could point to constipation. However, you know what is normal for your dog.
Systemic signs of constipation in dogs
Additionally, dogs may also show some systemic signs of constipation. These changes may be due to the absorption of toxins from the retained fecal material. Or they might relate to the underlying cause of the constipation. Some include:
- Vomiting: As the colon fills up and waste products enter the bloodstream, the dog may be nauseous and start vomiting. Or the vomiting could be due to the underlying problem causing the constipation.
- Inappetence: Dogs who can’t poop often don’t want to eat, either.
- Lethargy: Your dog may be sleeping or lying around more than usual. Lethargic dogs are also less interested in going on walks or playing.
- Dehydration: Your dog’s gums may look dry, his or her skin may stay tented, or the eyeballs may look sunken.
When should you go to the vet for a constipated dog?
The two main indicators of when to go to the vet are how long it has been since your dog pooped and how your dog is acting overall.
Generally speaking, if your dog has not pooped in 48-72 hours, it may be time to head to the vet. However, keep in mind that dogs normally may not poop for a few days after surgery. And they also are going to poop less if they aren’t eating or have just recovered from a bout of diarrhea.
Additionally, even if it hasn’t been that long, if your dog is frequently straining and only getting small amounts of poop out (or no poop), not eating, acting painful or lethargic, vomiting, or otherwise doing something that worries you, seek veterinary attention.
If a dog’s constipation goes untreated, they can quickly lose weight due to vomiting, lack of appetite, and electrolyte disturbances. Thus, it is important to seek veterinary attention for constipated dogs.
Sometimes “constipation” is not really constipation
Interestingly, dogs with a urinary tract problem or diarrhea may also appear to be constipated. Overall, diarrhea is more common than constipation in dogs, and it can cause straining and frequent posturing to defecate. Especially if you don’t see the diarrhea, you may understandably think the dog is constipated.
Straining to urinate due to a urinary obstruction or UTI in dogs can sometimes look a bit like straining to defecate, too. Urinary obstructions are an emergency. So, if your dog is straining and not passing much urine or only dribbling urine, make an emergency vet visit immediately.
How will the vet diagnose constipation in dogs?
Diagnosing constipation and identifying the underlying cause involves taking the symptoms, exam findings (including rectal exam findings), and results of additional diagnostic tests into consideration.
First, the veterinarian will gather your pup’s medical history and perform a thorough physical examination. For some constipated patients, the vet can feel a distended colon filled with feces when palpating the abdomen. Plus, he or she may notice signs of muscle or joint pain, weakness, neurological issues in dogs, or dehydration during the physical.
Rectal exam
As part of the physical exam, the vet will conduct a rectal examination to rule out abnormalities of the anus or within the rectum. These include strictures, polyps or masses, and, in male dogs, an enlarged prostate.
Additionally, rectal exams allow the vet to assess stool consistency and contents. This helps identify foreign material in the stool that could be blocking the rectum. And it gives the vet a better idea of how firm the stool actually is.
Additional diagnostic tests
Depending on your dog’s symptoms and the potential underlying causes of the constipation, the vet may recommend additional diagnostics. This could include X-rays to look for pelvic fractures, foreign objects in the GI tract, megacolon, and/or signs of arthritis. Or the vet may use bloodwork for dogs to screen for diabetes, hypothyroidism, kidney disease, electrolyte abnormalities, and other issues.
What is the treatment for constipation in dogs?
To treat dog constipation, the vet will need to rehydrate the dog, relieve the constipation, and address the underlying cause.
Rehydrating the dog and correcting electrolyte imbalances
Sometimes it will be necessary to rehydrate a constipated dog with IV fluids, especially if he or she is severely constipated, obstipated, or has a condition that leads to dehydration. This is the case because dried stools lead to fluid loss and cannot be evacuated in dry conditions. Plus, some treatments for constipation pull fluid into the colon, which can cause further dehydration.
While rehydrating the dog, the vet can also address any electrolyte imbalances noted on bloodwork.
Administering enemas to remove impacted stool
Once electrolytes and hydration are improved, the veterinarian can carefully administer an enema to loosen the stool and, hopefully, get the dog to pass it. To reduce the risk of colonic perforation, typically only the veterinary team should perform enemas.
Do not give your dog an enema at home unless directed by your vet to do so. And especially do not administer a Fleet® enema. Doing so is dangerous due to the risk of electrolyte imbalances, dehydration, GI upset, and other signs of Fleet enema toxicity in dogs.
Removing the stool manually
Occasionally, it will be necessary to manually evacuate the stool under general anesthesia when the constipation is severe, and other methods have been unsuccessful.
Using laxatives
Once your dog is well hydrated, the vet may start giving oral laxatives. Adequate hydration is important because laxatives work by pulling water into the colon to soften stool.
In addition to using them in the clinic, the veterinarian may send your pup home with oral laxatives for short-term or long-term use.
However, you should not use over-the-counter laxatives on your dog without your veterinarian’s approval. Some may contain ingredients that are toxic to dogs.
Improving colonic contractions with medication
Dogs with chronic constipation may need to take cisapride or bisacodyl. Both of these medications enhance smooth muscle contractions of the colon. This can help with colonic emptying.
Addressing the underlying cause
Since there are many reasons a dog could become constipated, addressing the underlying cause can look different from case to case.
It might involve a short-term solution like antibiotics and pain meds for an anal gland abscess. Or the vet may modify the existing management plan for a chronic condition. This could be something like adding regular subcutaneous fluids for dogs with kidney failure to improve hydration.
Your dog’s vet will work with you to create a plan that is right for your dog.
Performing surgery for dogs with constipation
Occasionally, if the dog has megacolon or ongoing episodes of constipation or obstipation that don’t respond to medical management, the vet may recommend a subtotal colectomy. This specialized surgery involves removing most of the colon in an effort to permanently resolve the constipation and/or megacolon.
However, some dogs will end up with chronic diarrhea instead, so you might be trading one problem for another.
Creating an ongoing constipation management plan
If the vet thinks it is likely your dog will continue to struggle with constipation, he or she may work with you to develop a constipation management plan. It will likely include increasing fiber and other measures. (More on prevention soon.)
Should I give my constipated dog more fiber?
Fiber for dogs can be a great way to naturally improve bowel movements, but it is best to consult your vet before adding a fiber supplement to your dog’s diet. Your vet can help you determine if fiber is right for your dog, which fiber supplement to use, and how much to give to your dog.
Fiber supplements work best for constipation-prone dogs who have normal colon function and are not dehydrated or suffering from electrolyte imbalances.
Giving fiber to dogs who are already dehydrated or severely constipated isn’t likely to solve the problem. And it might even make it worse. This is why it is so important to work with your vet if your dog is having trouble with constipation.
Ways to add fiber to your dog’s diet
For some dogs with mild constipation, the vet may recommend high fiber diets and supplements. Prescription foods such as Royal Canin® Gastrointestinal High Fiber diet contain the soluble fiber supplement, psyllium. Psyllium, which helps form a gel-like substance around stools to make defecation easier, is also the active ingredient in Metamucil for dogs.
Safety note: If your vet recommends Metamucil or a different human fiber supplement, ensure you use the unflavored powder form. Gummies, chews, or flavored powders may contain xylitol (birch sugar), which is toxic for dogs.
Wheat bran is another supplement ingredient used to add fiber to your dog’s diet. This type of fiber bulks up stool and distends the colon, triggering motility. Wheat bran is one of several active ingredients in Purina® Pro Plan® EN Fiber Balance diet. And it is found in supplements such as Glandex® chews, which help prevent anal gland issues.
Finally, canned pumpkin for dogs is another option for boosting fiber intake. However, it does not provide as much fiber as psyllium or wheat bran. Ensure you use plain canned pumpkin puree, not pumpkin pie filling. The pie filling version has added sugar and spices, which could be dangerous for your dog.
Are there home remedies for constipation in dogs?
When your dog gets to the point that he or she is feeling sick or uncomfortable from constipation, home remedies are generally not going to be enough. He or she needs veterinary care.
However, for very mild constipation, you could consider taking your dog for a walk to get the bowels moving.
It can also be helpful to increase water intake by ensuring your dog always has fresh water available, adding water to the dry food, or feeding some canned food. Or you could give your dog some canned pumpkin for dogs (not pumpkin pie filling).
If this doesn’t work or your dog worsens, bring him or her to the vet promptly.
Home remedies to avoid for dogs with constipation
Do not give any of these home remedies to your dog unless directed by your veterinarian.
- Mineral oil: While it is lubricating, frequent use of mineral oil can also inhibit nutrient absorption. Plus, you should never syringe it into your dog, because if your dog accidentally inhales it rather than swallows it, this can lead to pneumonia.
- Coconut oil: While it commonly shows up as a home remedy for constipation in dogs, coconut oil may cause stomach upset or pancreatitis in dogs before it improves bowel movements. (The same is true for olive oil.)
- Prunes: They are a common human constipation remedy, but the high sugar content of prunes means they are not a good choice for relieving constipation in dogs.
- Milk: Not all dogs digest the lactose in milk well, which can lead to gas and discomfort. Plus, it isn’t likely to resolve the constipation.
- Over-the-counter human constipation remedies: Do not use any human stool softeners, laxatives, or enemas on your dog without your vet’s approval. While some products are suitable for dogs, choosing the wrong one or using it incorrectly could be dangerous.
What is the prognosis for dogs with constipation?
The prognosis for constipation in dogs depends on the severity of the constipation and the underlying cause. Mild constipation that resolves without veterinary intervention carries a good prognosis. However, constipated dogs who require veterinary care for their constipation may be more likely to have recurring episodes and/or constipation that is harder to manage.
How can you prevent constipation in dogs?
While it isn’t going to be effective all the time, there are some strategies you can use to decrease the chances your dog will develop constipation (or become constipated again). They include:
1. Encourage water intake
Changing the water in the dish frequently, adding ice cubes to the water, using a water fountain, and having multiple water dishes can all encourage your dog to drink more water.
Additionally, since the water content of canned food is high, switching to canned food or adding canned food to the dry food can sneak in some extra water. To avoid sudden changes in diet, which can cause GI upset, it is best to find a canned version of the food your dog is already eating, if possible. Or, you can add water to the dry food instead.
2. Exercise your dog regularly
Getting moving helps the bowels stay regular. The amount and type of exercise that is right for your dog may vary depending on his or her age and physical status. For an arthritic senior dog, even taking a short walk (if he or she can do so comfortably) may help.
3. Ask your vet about adding a fiber supplement to your dog’s diet
As mentioned earlier, fiber can sometimes improve stool quality and consistency. Your vet will help you determine whether a prescription diet, fiber supplement, or just canned pumpkin is right for your dog.
4. Diligently watch for changes in your dog’s health
Taking the time to regularly perform a 5-minute dog wellness scan can help you catch some of the health problems that could lead to constipation. And paying attention to your dog’s stool quality, frequency, consistency, and contents is a good way to quickly notice when something is off, too.
If your dog shows signs of becoming constipated, or you find something abnormal on your health scan, contact your vet promptly.
5. Work with your vet to manage underlying problems
Your vet can help create a plan for dogs who have long-term neurological impairment, chronic disease, or other risk factors that may predispose them to constipation. Following that plan and keeping in contact with your vet can decrease the chances your dog will become constipated.
6. Keep your dog from eating non-food items
As much as possible, try to prevent your dog from eating bones, rocks, dirt, hair, and other items that could get stuck in the colon (or elsewhere in the digestive tract).
Don’t delay in getting help for a constipated dog
There are going to be times when your dog might not poop as often as expected, and it can be hard to know what to do. Thankfully, most of the time, your dog does end up having a bowel movement on one of the next few walks.
However, if your dog has gone more than 48-72 hours without passing stool (or more than a tiny bit of stool), is straining and/or acting uncomfortable, or is showing systemic signs like lethargy or vomiting, consult your vet. The sooner you seek help, the sooner your dog can start feeling better.
Is your dog prone to constipation?
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