What conditions can cause ascites in dogs and cats?

Ascites has many possible causes, including heart problems, liver or kidney dysfunction, abdominal infection, and tumours. The exact cause requires imaging, blood tests, and fluid analysis by your vet — please follow their recommendation for further investigation.

What tests will the vet perform to find the cause of the ascites?

Common tests include a physical examination, X-rays, abdominal ultrasound, blood tests, and fluid tap analysis. Advanced imaging (such as a CT scan) or specialist referral may also be recommended to clarify the underlying cause.

Is a fluid tap painful or risky for my pet?

Abdominocentesis is performed under sterile conditions by a vet and is usually completed quickly with pain relief or mild sedation as needed. The goal is to relieve respiratory or abdominal pressure. Risks vary depending on the individual patient — ask your vet about precautions before the procedure.

What should I do if I notice my pet's belly is swollen?

Start recording the timeline, food intake, and breathing at home, take photos or videos of any abdominal changes, and seek veterinary attention promptly. If your pet is having difficulty breathing, shows altered consciousness, or the abdomen is expanding rapidly, go to an emergency clinic immediately.

How much do the tests and treatment usually cost?

Costs vary by clinic and region — ask your vet for an estimate before proceeding.

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Disease Guide

Ascites in Dogs & Cats: Symptoms, Diagnosis & Care Guide [2025]

Ascites is a symptom, not a disease — common causes include heart disease, liver disease, tumours, or infection; identifying and treating the underlying cause is essential

Take 1 minute to check the symptoms first

Last updated: 2026/01/05

Pethealthmap Editorial Team

Sources: ACVIM, WSAVA, National Taiwan University Veterinary Hospital

When to See a Vet

Seek Emergency Care Immediately

•Rapid breathing or open-mouth panting requires immediate veterinary attention
•Altered consciousness or collapse requires emergency care right away
•Rapidly distending abdomen or marked abdominal tenderness requires immediate veterinary attention

Schedule a Clinic Visit Soon (within 24–72 hours)

•Noticeably reduced activity level lasting more than one day
•Significant decrease in appetite or not eating for multiple days
•Progressively enlarging abdomen or taut abdomen on palpation

01What symptoms indicate something is wrong?

Ascites is the accumulation of excess fluid in the abdominal cavity. Affected pets commonly show changes in general demeanour, breathing, or abdominal appearance. The symptoms below include common signs as well as those that may require urgent veterinary attention.

Lethargy, noticeably reduced activity, or excessive sleepiness
Decreased appetite or refusing food for several consecutive meals
Repeated vomiting or frequently bringing up food
Shallow, rapid breathing or open-mouth panting
Visibly distended abdomen — pot-bellied appearance or firm to the touch
Swelling of the abdomen or limbs (pitting or non-pitting oedema)

Seek emergency care immediately if you notice the following symptoms:

⚠️ Rapid or laboured breathing / open-mouth panting — seek veterinary care
⚠️ Altered consciousness or collapse — go to an emergency clinic immediately
⚠️ Rapidly enlarging abdomen or obvious abdominal pain — seek veterinary care

02How do you assess the situation at home? Key observations and emergency criteria

These are the key observations to make at home before your vet visit. This information helps your vet assess the situation quickly and arrange appropriate tests.

Note when the lethargy or reduced activity started and how it has progressed
Measure and record daily food and water intake
Track vomiting frequency, appearance (blood-tinged or bile-coloured), and any material brought up
Count the resting respiratory rate and note whether your pet is breathing with visible effort
Take photos or videos of the abdominal appearance, gait, and breathing pattern for your vet
Bring all written records, photos, and videos to your appointment

03How will the vet diagnose this? Common diagnostic tests

Your vet will combine a physical examination, imaging, and laboratory tests to confirm ascites, assess the likely cause, and gauge severity.

Physical examination

abdominal palpation and assessment of vital signs (heart rate, respiratory rate, mucous membrane colour)

X-ray

to evaluate for masses, organ abnormalities, or large fluid volumes in the chest and abdomen

Ultrasound

to quantify fluid, identify a safe site for fluid sampling, and examine organ structures

Abdominocentesis (fluid tap)

fluid is collected for cytology, biochemistry, and bacterial culture

Blood tests

to assess liver and kidney function, electrolytes, and infection or inflammation markers

Advanced imaging (CT scan)

used in complex cases or when detailed anatomical evaluation is needed

A specialist or well-equipped clinic with ultrasound and fluid-sampling capability is recommended

04How is ascites treated and managed? Medication, diet changes, and home care

Management of ascites focuses on identifying and addressing the underlying cause, while relieving the pet's discomfort and monitoring recovery.

The primary goal of treatment is to find and address the underlying cause of the ascites
Abdominocentesis may be performed when needed to relieve breathing difficulty or abdominal discomfort
Adjust diet and fluid management as directed by your vet, and monitor body weight and abdominal girth
Attend regular follow-up appointments for blood tests and imaging to assess treatment response
At home, keep your pet rested, limit strenuous activity, and monitor for any changes in symptoms
Long-term specialist follow-up and further investigations may be recommended

05What should you prepare before your vet visit? Key information to help your vet quickly identify the cause

Note when symptoms started, how they developed, and any sudden changes

List all current medications, supplements, and how often they are given

Prepare photos or videos of any vomiting or unusual stools for your vet to review

Record any recent changes in food intake, water consumption, urination, and bowel habits

Bring any previous test reports, imaging results, or medical records (if available)

Use a secure carrier and book your appointment in advance to minimise waiting time and stress

This content is for reference only and cannot replace a professional veterinary diagnosis. If your pet shows signs of illness, please seek veterinary care promptly.