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My Dog Has a Swollen Stomach but Acts Fine [Vet Answer]

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vet exam of the stomach for french bulldog

A swollen stomach can be a serious sign that merits urgent veterinary attention. However, if your dog is acting normal and seems fine (with no other signs of illness), it is probably not an emergency. Abdominal swelling is quite common and can occur in dogs of any age and breed.

As a veterinarian, one of the most important pieces of information to me is whether the abdomen seems 1) tense like an over-filled balloon or 2) soft and squishy. This helps us determine what could be contributing to the swelling.

Why does my dog have a swollen stomach but acts fine?

There could be several reasons:

1) Your dog is not experiencing discomfort: Typically when your dog seems well despite a stomach swelling, it is because they are not in much (if any) discomfort and they may not have even noticed that their abdomen is swollen.

2) Your dog is in the early stages of a disease: We also need to consider that your dog may be in the early stages of a medical issue, so they may not yet show other signs of illness. It is quite possible that additional symptoms are soon to follow.

3) Your dog is good at hiding discomfort: Finally, some dogs are very stoic. This means that, even when in a lot of pain, they can put on a brave face and try and act as if all is well. Some of the breeds known for this include the Pitbull Terrier and Staffordshire Bull Terrier.

Common causes of swollen stomach in dogs (when the dog otherwise acts fine)

When your dog is acting normally but you can see their stomach is swollen, some of the more common causes would include:

1. Over eating

If your dog has eaten a lot more food than usual, they may develop a large belly. This can be seen, for example, if a dog gets to an open kibble bag and polishes the whole thing off. As the dog gets a bit more uncomfortable, you may notice that they seem lethargic and are moving about less.

For most, mild exercise and time will resolve the issue and the swelling will gradually go down as the dog burps, farts and poops. It would be very uncommon to need to seek vet attention for this issue.

dog not eating

2. Gas build up

When there is a lot of gas within the intestines or stomach, we may notice that the abdomen seems larger than usual and is tense. Gas build up is most often seen in younger dogs, as their abdominal muscles are quite weak, so any gas build up is quite easy to see from the outside. Pups are also prone to bloating as they can eat quickly.

For most dogs, any swelling won’t last long and should not cause other symptoms. It can help to feed your dog in smaller portions and to use slow feeder bowls, to ensure they don’t gobble their food up too quickly. Light exercise helps to keep the gut moving and allows the dog to pass the gas naturally.

measuring dog belly with tape

3. Mild to moderate constipation

If a dog has not passed stool for a few days, we might notice their abdomen is bigger than usual. This is especially true when they have a lot of gas built up alongside the stool. Constipation is not very common but can occur when a dog is not drinking enough or when the dog is not being as active as usual.

Constipation can often be treated at home by increasing the dog’s daily exercise, improving their hydration and gently massaging their tummy. If your vet agrees, it may also be a good idea to offer a small amount of a laxative such as Lactulose. View our remedies for constipated dogs.

For more severe constipation, or when your dog also has signs such as straining, food refusal or lethargy, a vet visit is needed. Some dogs will need an enema, to help relieve their constipation.

pug straining to poop at the park

4. Internal parasites

Parasites such as worms can cause the abdomen to swell up, particularly in very young and slender dogs. This swelling may be readily visible at all times, or may be more easily seen after meals.

There may or may not be other signs, such as diarrhea, excess hunger and bloody stool or stool with worms. As worms are so common in puppies, they should be routinely treated for them from a young age. This can be done from home and worming puppies is both effective and inexpensive. Worms will sometimes show up in your dog’s poop, as shown on the picture below.

collage picture of worms in dog poop

5. Fluid build up

When there is excess fluid within the abdomen, it can seem squishy and soft. Fluid can build up slowly over time, or quickly in a matter of hours. The fluid can be a range of things including blood from a ruptured tumor, ascites due to liver failure or fluid build up secondary to low protein levels.

As more and more fluid builds up, we may start to see signs. This can include panting, pale gums, weakness or a cough. Any sort of fluid build up within the abdomen is unusual and warrants urgent vet attention. Your vet will want to assess what type of fluid it is, which may involve blood tests, imaging and aspiration of the fluid.

Disclaimer: This content is not a substitute for veterinary care. Always consult with your vet for health decisions. Learn more.

closeup of abdominocentesis in Dog

6. Organ enlargement or a mass

When an organ such as the spleen or liver enlarges, this will make the abdomen seem swollen. The same effect is seen when there is an abdominal tumor. This will be a firm swelling that tends to enlarge slowly over a matter of weeks or months. The swelling would be more noticeable in slimmer dogs.

Dogs won’t be aware that their organ is enlarged and other symptoms are rare initially. However, we may start to see signs as the disease progresses. For example, if the liver is failing, we would eventually see symptoms including jaundice, nausea and weight loss.

If your vet suggests an organ is enlarged after feeling your dog’s abdomen, they will want to perform some imaging, to determine what is enlarged. They may then biopsy the organ, in order to make a treatment plan.

Early symptoms of swollen stomach in dogs

When your dog’s stomach enlarges, you will be able to visibly see this. For dogs who are well-muscled or fat, it may take longer for the swelling to become obvious. Owners may notice that the abdomen feels more tense or perhaps softer, depending on the cause of the swelling.

Initially, there may be no other signs. However, as time goes on and the issue progresses, you are likely to start notice new symptoms. Let’s look at symptoms that would call for a visit to your vet.

Veterinary visit or wait and see?

When you know why your dog’s abdomen is swollen and you’re happy you can resolve this from home, you may not wish to seek veterinary care just yet. However, if your intervention does not rectify things or if your dog starts to become unwell, a vet visit is required. At any time, if a swollen abdomen is accompanied by more worrying signs, an urgent vet visit is needed. These signs include:

  • A chronic cough or panting
  • Pale gums
  • Lethargy
  • Food refusal
  • A fever
  • Persistent drooling or gagging
  • Distress or restlessness

3 things to try at home to help your dog

If your dog isn’t showing any of the signs listed above, or any other signs of illness, you can try the following home remedies to help your dog after talking to your vet:

1. Try mild exercise: Time may resolve the issue and the swelling will gradually go down if the issue was over eating. Your dog should be happy to go on a slow stroll, and be sure not to overdo it.
2. Feed your dog in smaller portions. You can also consider using slow feeder bowls, to ensure your dog doesn’t gobble their food up too quickly.
3. Try remedies for constipated dogs: If your dog hasn’t pooped in the last 48 hours, try our remedies for constipated dogs.

WATCH: 3 Important Tips To Care For an Old Dog [VET VIDEO]

If things don’t improve after a few hours or your dog seems uncomfortable, call your vet for further advice.

When does a swollen stomach become a serious case for dogs?

In some instances, abdominal swelling is not a big concern, and can be treated from home. This is the case, for example, in a puppy with worms or in a dog who has eaten too much of their kibble.

However, when your dog’s abdomen is swollen and you don’t know why, this could be a sign of a serious medical issue. Any swelling you cannot explain, should be looked into by a vet.

Treatment options and likely costs

How we treat a swollen abdomen will ultimately depend on its cause. Some of the more ‘simple’ issues like parasites or over indulgence can be treated at home for little to no money. A wormer usually costs less than $10.

For more complex and sinister issues like fluid-build up or an abdominal mass, the treatment will be more complicated. Some masses (such as splenic tumors) can be removed. This surgery will set an owner back around £2,000.

Conditions such as liver disease can be managed with ongoing medication and a prescription diet. Depending on the cause of the liver disease and the diagnostic tests needed, the bill may come to between £1,500-4,000.

Frequently Asked Questions

Can I wait and see if the swelling goes down on its own?

In some instances, this is a sensible option. For example, if you know your dog has managed to eat their dinner and the meal of another dog in the home, we’d expect any swelling to be mild and temporary.

Should I induce vomiting if I suspect my dog ate something harmful?

If you think your dog has eaten something toxic, you need to call a poisons helpline or vet. We will not always want a dog to vomit, even if they have eaten a toxic. Some chemicals can damage a dog’s food pipe when vomited, so it is always important to double check with a professional.

Can a swollen stomach be a sign of pregnancy in female dogs?

The abdomen can be a bit swollen due to fluid buildup during a false pregnancy. The abdomen will also look enlarged when a female is truly pregnant, as the uterus enlarges and the fetuses grow. As well as this, we should see mammary enlargement, which can make the abdomen seem even larger. If you have a female who is not neutered, consider that their abdominal swelling could be due to a true pregnancy, false pregnancy or uterus infection (pyometra).


  • Dr. Linda Simon, Veterinarian

    Dr Linda Simon (MVB MRCVS) has 10 years of experience as a veterinarian. She is a veterinary surgeon with a special interest in geriatric patient care, dermatology and endocrinology. She is a member of the British Royal College of Veterinary Surgeons. She graduated top of her class from UCD School of Veterinary Medicine in Dublin in 2013. Linda has also worked as a locum vet in a range of clinics, including 24 hour emergency clinics and busy charity clinics.

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