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Home > Cats > Why Your Cat Is Leaking Poop: 8 Concerning Causes (Vet Answer)

Why Your Cat Is Leaking Poop: 8 Concerning Causes (Vet Answer)

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Written by

Dr. Karyn Kanowski

Veterinarian, BVSc MRCVS

The information is current and up-to-date in accordance with the latest veterinarian research.

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Fecal incontinence is a distressing syndrome to be faced with, both for you and your cat. For a species that is inherently clean, the inability to control their defecation may be as upsetting for your cat as it is for you. Fecal incontinence has several different causes, and these are important to be able to recognize, as the cause will ultimately determine whether or not the incontinence can be treated.

Before we examine the eight causes of fecal incontinence, it is important to first understand that there are two subsets into which this condition falls: problems affecting the rectum or intestine which make it difficult or impossible to control defecation, also known as reservoir incontinence. With this type of incontinence, the cat is usually aware that they are passing feces, but unable to control it. Sphincter-based incontinence, where dysfunction of the anal sphincter allows poop to exit with little or no resistance. Cats are usually unaware that they have passed feces in this type of incontinence.

We will now examine four causes of reservoir incontinence, followed by four causes of sphincter incontinence.


Reservoir Incontinence

1. Diarrhea

This is probably the most common reason for fecal accidents in cats, but fortunately, also the most readily treated. Diarrhea in cats can happen for many reasons, such as eating something they shouldn’t, infection, or an inappropriate diet. The increased passage of liquid feces can catch cats off guard, leading to episodes of leaking poop, but this will quickly settle once the cause of diarrhea has been treated.

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2. Constipation

You might think that constipation would be the polar opposite of fecal incontinence, but sometimes, the pressure from straining against constipation can result in small pieces of poop dropping out. You may also see small amounts of liquid feces leaking from the constipated cat. This is the result of fluid being able to pass the fecal blockage and leak out because the rectum is inflamed from straining. Treating the constipation will usually resolve this issue unless there is longer-term damage that leads to megacolon.

3. Megacolon

This is a condition where the rectum becomes stretched or dilated, prohibiting it from functioning normally. This is a condition that can be caused by a blockage, constipation, strictures, or cancer, but often occurs with no known inciting cause.

This is then known as idiopathic megacolon, and it is the most difficult to treat. For some cats, megacolon is a lifelong condition that needs to be managed with a combination of medications and high-fiber diets to help maintain the normal function of the rectum and keep things moving.

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4. Intestinal worms

This is not a common cause of fecal incontinence, but the inflammation caused by intestinal worms, particularly in young cats, can lead to hypermotility (increased speed and intensity of passing poop) and cause leaking or accidents. The treatment and prevention of intestinal worms will eliminate this problem.


Sphincter Incontinence

5. Age

In a geriatric cat, the elasticity of the anal sphincter may weaken, resulting in leaking poop. It is rarely large amounts and may just be a nugget or two in the bed. Providing a high-quality diet may help to reduce the incidence of age-related fecal incontinence, but it is likely that older cats will still have the occasional accident. It is important to take your aging cat for a check-up with your vet, as fecal incontinence can also be a sign of arthritis.

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Image Credit: Bogdan Sonjachnyj, Shutterstock

6. Arthritis

Older cats commonly suffer from arthritis, particularly in their elbows, hips, and knees. When this happens, it becomes harder to get into and maintain, the appropriate posture to poop, and cats may delay going to the toilet as long as possible to avoid the discomfort. This can sometimes result in feces building up and pushing against the sphincter which is unable to keep it in. Starting your cat on anti-inflammatory pain relief will go a long way in improving your geriatric cat’s quality of life, not to mention the quality of their anal tone, so be sure to visit your vet.

7. Injury

Injuries to the pelvis, tail, and spine can damage the nerves that control the anal sphincter. It is common for cats to suffer pelvic fractures if they are hit by a car, and this can cause compression of the nerves. Tail-pull injuries in cats can also be disastrous, resulting in damage to nerves that control the anal and urethral sphincters, bladder tone, and even motor function of the hind limbs.

Swift surgical intervention of a pelvic fracture may allow full nerve function to return, although not all pelvic fractures require surgery. It is, therefore, important to assess a cat’s urinary and fecal continence following this type of injury.

In the case of tail pull injuries, high amputation of the paralyzed tail is often performed in an attempt to alleviate the traction effect the limp appendage has on the nerves.

However, some nerve damage is severe, and in these cases, fecal incontinence will be permanent, an outcome that often results in euthanasia.

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8. Cancer

Tumors involving the anal sacs, anal sphincter, or rectum can cause deformation of the anus, allowing poop to leak. Depending on the size, location, and type of tumor, surgical removal may resolve this problem, but it must be noted that surgery in this area is often complex and may cause problems to the structures and nerves.


A Note on Anal Sacs

Cats have anal sacs, which are scent glands, located on either side of the anus, just inside the rectum. These glands are expressed when the cat passes feces or is frightened. The fluid expressed by these glands has a powerful scent that cats use to communicate with one another. Sometimes the fluid from these glands will leak, and you may notice a very pungent, fishy odor. This is not fecal incontinence, but if the anal glands leak often, it could be a sign of a problem, so it is worth taking them to the vet.

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Image Credit: Andy Gin, Shutterstock



Fecal incontinence in cats is a condition that can have a wide range of causes, eight of which we have examined here. When cats leak poop, it can be due to problems with the rectum or large intestine (reservoir incontinence), or issues with the anal sphincter (sphincter incontinence). Fortunately, many of the causes of fecal incontinence in cats can be treated by addressing the underlying cause; however, there are some circumstances in which the condition is permanent.

Regular worming, the feeding of a high-quality diet, and managing the pain and inflammation of arthritis are all things that can help prevent the problem of leaking poop in cats. Permanent nerve damage or invasive tumors, however, will typically result in fecal incontinence that will not resolve, often resulting in palliation (end-of-life care) or euthanasia.

Featured Image Credit: Litter Robot, Unsplash

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