Why Is My Dog Constipated?

Is your dog constipated? The signs, what can cause it, what not to do at home and when to call your vet.

Quick Answer

Constipation means a dog strains to poo but passes very little or nothing, because stool that stays in the colon loses water and becomes hard.
Vets Now says swallowing things that are hard to digest, such as bones, grass or hair, is the most common cause. Other possible causes include dehydration, pain, matted fur around the bottom and some illnesses.
If your dog is straining, seems in pain or has not pooed in 24 hours, call your vet.
Do not give a laxative, milk or an enema yourself, because laxatives are for when a vet advises them and enemas must only be given by a vet.
If you think your dog has swallowed something that could block its gut, call your vet immediately.

Is your dog constipated? Constipation means a dog strains to poo but passes very little or nothing. PDSA explains that when poo stays in the colon it loses water and becomes hard, which makes it difficult to pass.

Most dogs poo one to three times a day, but every dog is different. So contact your vet if your dog's habits change. VCA describes constipation as infrequent or hard-to-pass stool that is usually temporary.

Obstipation is the severe form, where a dog cannot pass the stool at all. It is often tied to a serious or lasting condition.

Calm white dog walking slowly on green grass in a park, where an owner may first notice their dog constipated and straining

What Can Leave a Dog Constipated?

Swallowing things that are hard to digest

Vets Now calls swallowing indigestible items the most common cause. Examples include bones, grass, hair and plant matter. PDSA adds that a blockage in the gut or anus can also lead to constipation. PDSA says never to feed bones as treats, and VCA advises limiting access to bones.

Diet, water and exercise

Low fibre or very little exercise can contribute. The Royal Kennel Club adds that too much fibre can also cause problems. In addition, not drinking enough, or anything that causes dehydration, can lead to hard stool. VCA also lists a sudden change of diet, or eating new foods, as a possible contributor.

Pain that makes it hard to get into position

Pain can make it hard for a dog to get into the right position to poo. Possible reasons include sore back legs or hips from arthritis or hip dysplasia, a fractured pelvis, or anal problems.

Golden retriever walking in a park on a sunny day; regular exercise is part of the advice if you often find your dog constipated

Matted fur and anal gland problems

Matted fur around the anus can block the passage of poo. Vets Now says long-haired dogs, especially small ones such as Yorkshire terriers, can become distressed by matted poo around the bottom. Blocked anal glands are another possible cause.

Prostate problems in male dogs

In male dogs, an enlarged prostate or prostate cancer can cause constipation.

Growths, hernias and nerve problems

Intestinal or abdominal cancer, and tumours in the colon or rectum, can cause constipation. So can hernias and some nerve (neurological) disorders.

Illness, medicines and other factors

PDSA lists an underactive thyroid, colitis and some medicines as possible causes. It also lists being very overweight. Vets Now includes kidney disease, and VCA lists fear or anxiety.

Megacolon

Megacolon is a dilated, weak colon that causes severe constipation. VCA calls it a serious, though generally uncommon, consequence or cause of constipation.

Which dogs are at higher risk?

Vets Now says older dogs are more prone to constipation, though any breed or age can be affected. VCA adds that dogs with long hair, or that groom themselves excessively, are also at risk, and the Royal Kennel Club says smaller dogs are often more prone.

Signs of Constipation in Dogs

Different sources list slightly different signs. Together, they include:

Whining or whimpering when pooing, or crying out
Straining for longer than usual, or repeatedly
Passing only small amounts, or small, hard, dry stools
Blood or mucus in the poo or around the bottom
Over-grooming the back end, circling, scooting or frequent squatting
Thin, ribbon-like poo
Redness or swelling around the anus
A tense, hard or painful abdomen
Reduced appetite or vomiting

If constipation goes untreated, Vets Now says dogs may also become lethargic or low in mood.

Small amounts of liquid stool can leak past a blockage, and VCA says this can be mistaken for diarrhoea. MSD says that if an enlarged prostate, a mass or enlarged lymph nodes get in the way, poo may look thin or ribbon-like.

Straining to urinate can look like straining to poo, so check which one your dog is trying to do. PDSA says tail position can help, as it is often up for pooing and down for weeing.

What You Can Do at Home

PDSA says that if your dog is otherwise healthy, keeping up exercise, plenty of water, a healthy weight and a suitable diet can help. The Royal Kennel Club adds a few practical tips, and says it is always worth checking with your vet first:

Give constant access to fresh water.
Ask your vet whether wet food could be tried instead of dry.
Keep a regular feeding routine.
If you do switch foods, do it gradually over about 7 to 10 days, and speak to your vet before making any diet change.

For visible problems around the back end, Vets Now suggests wearing rubber gloves, gently easing out any visible grass, and carefully trimming matted stool. If you are not confident doing this, ask your vet.

What Not to Do

Do not give a laxative unless your vet advises it, because the underlying cause may need investigating. The Royal Kennel Club also says not to give milk, as many dogs are lactose intolerant.

Do not give an enema yourself. Vets Now says enemas must only be given by a vet.

If you can see a thread or string at your dog's anus, do not pull on it. Vets Now warns this can cause internal damage.

Finally, do not ignore it. PDSA says constipation can get worse the longer you leave it.

Emergency: Contact a Vet Immediately If…

You think your dog has swallowed something that could cause a blockage. PDSA says never to wait to see if a problem develops, and never to try to make your dog sick at home.
Your dog has signs of a gut blockage, such as vomiting, abdominal pain (yelping or the "prayer position"), lethargy or reduced appetite. PDSA says a blockage is very serious, painful and can kill.
Your dog has blood, swelling, soreness, pus, protruding tissue or growths at the anus, or is straining to pass faeces. Dogs Trust lists all of these as needing urgent veterinary attention.
Your dog has a swollen abdomen. Dogs Trust lists this among the signs that need urgent veterinary attention.
Your dog is straining to urinate but producing no urine. Dogs Trust calls this particularly serious.

Call your vet or the nearest out-of-hours emergency vet straight away.

When to Contact Your Vet

PDSA advises contacting a vet whenever a dog shows signs of constipation or struggles to poo, and says it is better to be safe than sorry.
Vets Now says to contact a vet if your dog has not pooed for more than 24 hours, or if you are worried.
Dogs Trust says to talk to a vet if constipation or diarrhoea lasts more than 24 hours. It adds that hard, dry faeces or difficulty passing them may signal diet problems, dehydration or illness.
The Royal Kennel Club says to call the vet as soon as constipation is suspected.

Advice varies on timing. VCA, a US source, suggests seeing a vet if there is no bowel movement within 48 to 72 hours of the last one. The cautious approach is to call your vet sooner: if your dog is straining, seems in pain or has not pooed in 24 hours.

How Vets Investigate and Treat Constipation in Dogs

Your vet will examine your dog and ask about toilet habits and general health. The exam may include a rectal exam, sometimes under sedation. They will also ask how long the problem has lasted, what your dog eats and what it may have swallowed. Further tests depend on the suspected cause and can include blood tests, faecal tests, X-rays and ultrasound.

Mild cases may need changes to diet and water intake, and possibly a vet-prescribed laxative and a small enema. Vets Now adds stopping access to unusual items and a high-fibre diet. VCA says some dogs need to be admitted to hospital for enemas and fluids, and PDSA says more severe cases might need an anaesthetic so the poo can be removed with a larger enema. Impacted stool may also need removing by hand, sometimes under anaesthetic.

The underlying cause is treated too. VCA says surgery may be recommended if constipation is severe and medical treatment is unsuccessful. It also says most dogs recover well after medical treatment, although some need lifelong treatment to keep their bowels moving normally.

Helping Prevent Constipation

Vets Now, the Royal Kennel Club and MSD all point to plenty of water. Vets Now and MSD also mention frequent chances to toilet, while the Royal Kennel Club adds regular exercise and a balanced, appropriate diet. Vets Now says to avoid giving bones.

How Pet Med Direct Can Help

Pet Med Direct is a UK online pet pharmacy. If your vet recommends a change of diet, you can browse our dog food range, including veterinary diets. Please check with your vet first, because constipation in dogs can have many different underlying causes.

If your vet prescribes a medicine, our guide explains how pet prescriptions work. You may also find our GI Upset in Dogs guide useful.

Some pet medicines require a valid veterinary prescription. Pet Med Direct can only supply prescription medicines after the prescription has been checked. Always follow your vet's advice and the directions on the medicine label.

Frequently Asked Questions

Should I worry if my dog has been constipated for more than 24 hours?

Vets Now and Dogs Trust both give about 24 hours as the point to contact a vet, and the Royal Kennel Club says a dog that has not pooed within 24 hours may be constipated. PDSA and the Royal Kennel Club say to call as soon as you suspect it. VCA, a US source, says 48 to 72 hours. The cautious approach is to call your vet at 24 hours or sooner.

Can I give my dog a laxative or milk?

No. Only use a laxative if a vet advises it. The Royal Kennel Club also says not to give milk, as many dogs are lactose intolerant. Enemas must only be given by a vet.

Is constipation an emergency?

It can be. If you suspect your dog has swallowed something that has caused a blockage, call your vet immediately. A swollen abdomen, or straining to urinate with no urine produced, is also an emergency.

How will a vet treat it?

That depends on the cause. Mild cases may need diet and water-intake changes. Some dogs need hospital treatment with enemas and fluids, and severe cases may need stool removal under anaesthetic.

How do I tell if my dog is straining to poo or to wee?

Straining to urinate can look like straining to poo. PDSA says tail position can help: it is often up for pooing and down for weeing. If you cannot tell, ask your vet.

Related Dog Health Guides

Sources and Further Reading

This article was researched from the sources listed above. It is general information for dog owners and is not a substitute for advice from your own vet.

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This article is for informational purposes only and does not constitute veterinary advice.
If you are concerned about your dog’s health, please consult a qualified veterinarian.