Cats, our beloved feline companions, can sometimes experience swollen bellies, and it's essential to approach this issue with compassion and understanding. There can be several reasons behind a cat or kitten's swollen belly, and it's crucial to explore these possibilities while keeping your furry friend's well-being in mind.

A cat's swollen belly can result from various factors, including organ enlargement, the presence of fluid or a mass in their abdomen, intestinal parasites, or weight gain. Your veterinarian plays a pivotal role in identifying the root cause of your pet's swollen belly, in some cases, a simple physical examination might reveal the answer. However, more often than not, additional testing becomes necessary to provide a comprehensive diagnosis.

Let's delve into some common causes of a cat's swollen belly.

Organ Enlargement

The abdomen contains numerous organs that can become enlarged, leading to a swollen belly.

1. Liver, Spleen or Kidneys

Enlargement can result from various causes, including types of cancer, infections (especially fungal diseases), inflammatory responses, or reactions to diseases affecting other parts of the body.

2. Bladder

An enlarged bladder and the inability to urinate can be signs of a urinary blockage, a potentially life-threatening condition. This condition is more common in male cats, but can also occur in females.


Fluid in the Abdomen

Moderate to large amounts of fluid in the abdomen can result in a cat or kitten swollen belly. Usually, if this is the case, the vet will be able to observe a fluid wave when they touch the area.

Fluid in the abdomen can be a result of numerous diseases:

1. Hemorrhage

Bleeding into the abdomen can be caused by bleeding tumors, trauma to internal organs, decreased platelet numbers or platelet dysfunction and the ingestion of a specific rat poison called an anticoagulant rodenticide.

2. Cancer

Cancer can cause fluid, and potentially blood, to accumulate in the abdomen.

3. Heart failure

Right-sided heart failure can lead to the inability to pump blood out effectively and result in a buildup of fluid in the abdomen. Any concern for heart failure should be considered an emergency and warrants prompt evaluation.

Intestinal Parasites

The presence of gastrointestinal parasites can make a cat look potbellied, notes the Cornell Feline Health Center. This is more commonly the cause of a kitten swollen belly as kittens are more likely to have large worm loads. Your vet can determine the presence of intestinal parasites by examining your cat's feces. Treatment normally consists of an oral medicine.

Abdominal Mass/Tumor

A mass or tumor associated with one of the many abdominal organs can result in a cat swollen belly. This is more common in adult cats. An abdominal mass can be benign or cancerous. Testing is necessary to obtain a specific diagnosis.

Based on the location and type of mass, treatment may involve surgery to remove the mass, chemotherapy or monitoring and supportive care with medications.


If your cat has a swollen belly, it is important to have him or her examined by their veterinarian. A thorough exam and diagnostic testing are essential to pinpoint the underlying cause. Common diagnostic tests include full bloodwork, urinalysis, abdominal ultrasound and/or X-rays, chest X-rays, fluid analysis, and biopsy (if a mass is present).  Additional testing for infectious diseases or organ function may be necessary. Your veterinarian will tailor the testing to your individual pet's case.


The treatment of a cat or kitten with a swollen belly depends on the underlying cause. It may involve procedures such as removing excess abdominal fluid, medications, or surgery. Throughout the treatment process, it's crucial to closely monitor your pet and follow up with your veterinarian if you notice any changes in their behavior or physical condition. If you ever have concerns about your cat's swollen belly, don't hesitate to reach out to your veterinarian for their expert guidance and support.

Remember that your cat's health and comfort are of the utmost importance. Approaching the situation with empathy and seeking professional veterinary care will ensure the best possible outcome for your cherished feline companion.

Dr. Jessica Seid Dr. Jessica Seid

Jessica Seid is an emergency veterinarian practicing in the New England area. She is a graduate of the North Carolina State College of Veterinary Medicine and has been in the field for more than a decade. When she's not helping patients, she enjoys spending time with her husband, daughter and French bulldog.