Swelling in the Stomach in Dogs

Why is my dog swelling in the stomach?

What is Swelling in the Stomach?

Your dog’s stomach can be swelling for a number of reasons which can range from normal to serious. Keep your dog healthy by knowing the signs of a serious stomach disease. Internal bleeding, pregnancy, roundworm infection in puppies or simply eating too much can all be causes of a bloated stomach. Here are some other reasons that your pet’s stomach may be swelling:

  • Gastric dilatation
  • Peritonitis
  • Cushing’s syndrome
  • Ascites
  • Intestinal obstruction
  • Tumors 

If you notice that your pet’s stomach appears to be swollen or bloated, they should be brought to the vet immediately, as some causes of stomach swelling are dangerous and need to be dealt with quickly.

Why Swelling in the Stomach Occurs in Dogs

Bloating occurs when there is gas or food that is stretching the dog’s stomach. Some causes are more serious than others. For example, enlargement of the stomach will occur naturally as a result of pregnancy, but if you suspect gastric dilatation, your pet should be brought to the vet immediately as it is an emergency.

Gastric Dilatation

This is a very serious illness that can only take a few hours to become fatal. Gastric dilatation occurs when the bloated stomach rotates and traps the gas inside of it, which cuts off the blood supply to the stomach. This disease can be extremely painful and can be triggered by exercising after a meal or swallowing a lot of air. Breeds who are deep chested, like the St. Bernard, Great Dane and Weimaraner are more at risk of developing it. Big dogs, or those who are 99 pounds or over, have a bloat risk of 20%. Although it is rare, this condition can also occur in small dogs. This illness can be passed down through the family, and therefore if your pet’s ancestors are known to have developed the condition, your pet may be at risk as well.  Older dogs, usually between the ages of 7 and 12, can also develop this disease more easily. The affected dog will become breathless and distressed, and the stomach will become very tense. 


Peritonitis is usually caused by a puncture or rupture that occurs in your dog’s intestine or stomach which can cause inflammation of the abdominal cavity’s lining. These can be caused by a splinter from a bone, tumors, ulcers, a bacterial infection from an external wound, perforation of an internal organ or other factors. This illness can also occur from a rupture in the urinary bladder or gallbladder. Dogs with peritonitis may show a reluctance to move, vomit, exhibit rapid breathing, black stools, unwillingness to lie down, diarrhea, weakness and loss of appetite or have swelling in the abdomen, and these symptoms will appear all of a sudden. Shock can often occur and will require emergency treatment. A low fever, jaundice, pale gums, a fast heart rate, fluid in the abdomen, low blood pressure, a mass in the abdomen and pain upon palpation will often be noted by your vet. 

Cushing’s Syndrome

This illness is also called hyperadrenocorticism, and it usually occurs when the pituitary gland is overproducing the cortisol hormone. It can be caused by a tumor on an adrenal gland, but this is uncommon. Dogs with this syndrome will have a pot-bellied look, and it is most common in dogs who are over the age of 6 years. Hair loss, excessive eating, drinking, and urinating as well as increased panting, are all symptoms of Cushing’s syndrome. This disease can cause neurological problems if left untreated long enough for the tumor to grow big enough to interfere with the brain.


Ascites is the term used for when there is an accumulation of fluid in the abdomen, which can eventually lead to abdominal distention. The accumulating fluid can also create difficulty breathing by putting pressure on the abdomen. Problems with the kidney, peritonitis, a hemorrhage, a rupture in the urinary bladder, heart failure on the right side, chronic liver disease, tumors in the abdomen and severe diseases in the intestines can all be causes of this illness. Dog’s who are affected can appear to be pear-shaped and may be reluctant to exercise and or be coughing and seem out of breath.

Intestinal Obstruction

Intestinal obstruction or blockage can occur if your dog eats something that they should not and it ends up getting stuck in the intestine. Toys, pebbles, coins, bones, beads or buttons are all examples of objects that can get stuck and lead to a blockage if ingested. Vomiting often, pain and swelling in the stomach, constipation and difficulty defecating, dehydration and a loss of appetite are all signs of a blockage in the intestine. Noticing these signs early on is important to prevent serious health issues.


Tumors that develop in the abdominal organs can cause enlargement and swelling. Depending on which organ is affected, you may notice different symptoms. Tumors can take weeks or months to form, and can also rupture, which can lead to bleeding in the abdominal cavity. Dogs who are between 7 to 10 years of age will more commonly develop tumors. Breeds who are predisposed to this type of tumor includes Staffordshire Bull Terriers, Rough-Coated Collies, and Belgian Shepherd dogs. Male dogs will also develop it more commonly than females. Signs can include chronic vomiting and a possibility of vomiting blood, stools that are black or tar-colored, abdominal cramps and a loss of appetite leading to weight loss.

What to do if your Dog is Swelling in the Stomach

Your veterinarian will most likely want to know how quickly the swelling occurred and what other symptoms were associated with it. Ultrasounds can be used to determine if there is any free fluid present as well as seeing the structure of the dog’s organs. It can be useful to get biopsies of specific organs as well as samples of free fluid. If you are considering surgery, blood samples can be beneficial to assess the functionality of some organs. If the vet suspects heart failure, chest and heart x-rays or ultrasounds may be necessary. X-rays of the chest can also be used in the case of a tumor. Diagnosing a gastric dilatation can be done by taking into consideration the history and a clinical examination. X-rays can be helpful for confirmation. Treatment for gastric dilatation will require emergency care immediately, which may include decompression of the stomach, stabilizing the heart, shock management and potentially surgery once the patient is stable. 

Diagnosing peritonitis will require ultrasounds and an analysis of the fluid in the abdomen. A complete blood count, a profile of blood chemistry, along with a urinalysis will occur before surgery. Treating peritonitis may include antibiotics, intravenous fluids, and medication to relieve the pain. It will also be necessary to perform surgery in order to remove the infected fluids, flush the abdomen and for reparation of the puncture. Your companion may have to remain in the hospital for three to seven days after undergoing surgery. 

For Cushing’s syndrome, treatment can include radiation, surgery or oral medication. Surgery is an option in the case of a tumor on an adrenal gland. The procedure and treatments for ascites will depend on what is causing it. It will be diagnosed by a physical exam, considering the history, and looking at results from blood and urine tests. The excessive amount of cortisol in the body can raise the chances of your pet getting bacterial infections. X-rays and ultrasounds may be used to check on the adrenal glands and liver, as they can become enlarged in dogs with Cushing’s disease. 

Bloodwork, urinalysis, x-rays and physical exams will be used to diagnose the true cause of your pet’s ascites. They will resolve once the underlying issue is cured. The appropriate medications and, in some cases, medical therapy will be used to treat ascites and to relieve pain. Sometimes, the fluid will need to be removed. X-rays of the chest, after having the dog swallow barium, will be used to diagnose tumors. 

To look for masses in the wall of the stomach, lymph nodes or tumors present in other organs, ultrasounds may be used. As a noninvasive method to collect biopsy and have access to direct visualization of the tumor, an endoscopy may be performed. In many cases, surgery will be the recommended treatment for stomach tumors. To stop the spread of the tumor, biopsies of the liver and lymph nodes will possibly be used. Many dogs will need to be hospitalized for 48 to 72 hours after surgery is performed.

Prevention of Swelling in the Stomach

Avoid using elevated water and food bowls, as they can increase the risk of gastric dilatation. You should also keep your dog from eating too quickly and prevent them from exercising right after a meal. Avoid intestinal blockages by keeping small objects that can be eaten and lead to blockages out of your pet’s reach.

The best way to prevent issues with your dog’s stomach is to bring them for regular checkups and be observant for any changes in their health or behavior. Regular visits to the vet will allow your veterinarian to monitor the heart, lungs, bowel, stomach and other organs. Examining your pet’s stomach on your own can also help you notice anything unnatural. To do this, gently feel for any tenderness to the touch, lumps, swelling, stickiness and hotness. Feed your dog multiple meals a day, as giving them only one can increase their chances of developing gastric dilatation. Including canned food in their diet can also be beneficial. Give your dog small pieces of kibble that can be eaten easily and only allow them to have toys that are bigger than their throat.

Cost of Swelling in the Stomach

Swelling of the stomach can be a symptom of many diseases and will have different costs for treatment. Gastric dilatation-volvulus can have a treatment cost of about $6000. Diagnosing and treating Cushing’s disease will cost $2000, and ascites will have an average cost of $1800 for diagnosis and therapy. Intestinal obstructions can require surgery and the expense may average around $3000.

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Swelling in the Stomach Questions and Advice from Veterinary Professionals


Shih Tzu




10 Years


7 found this helpful


7 found this helpful

My pet has the following symptoms:
Runny Nose
My dog is breathing fast and shallow. He had swollen neck lymph nodes and was put on some pretty powerful antibiotics. It seems that his lymph nodes aren’t swollen but his breathing is horrible. Short fast shallow breathing. He’s urinating and eating. His belly is distended some. Sounds like he’s snotty and sneezing and coughing.

March 27, 2018

7 Recommendations

You should return to your Veterinarian for a follow up examination to determine whether any further treatment is required; the breathing difficulty may be due to the ‘snotty nose’ or due to a distended abdomen. The distended abdomen is concerning as this may be causing breathing difficulties since the diaphragm cannot move whilst breathing, there are many causes for a distended abdomen which should be evaluated by your Veterinarian. Regards Dr Callum Turner DVM

March 27, 2018

Was this question and answer helpful?

Silky Terrier




7 Years


0 found this helpful


0 found this helpful

My pet has the following symptoms:
Vomiting - Distended Belly
Please help me understand..My silky terrier passed away last week. She was fine Monday. She had her dinner at 5:30pm and about 3 hours later vomited it back up. Tuesday afternoon she wasn't much better but she was drinking water.. Most of which came back up so we went to the vet. The vet took her temp and it was normal, she was 7 yr's old. and had Never been sick, she was not a chewer, She did not get bones or raw hides. Her stomach was swollen so they did an xray and said she had gas. They gave her a shot for the gas, a shot for the vomiting and a shot of anitbiotics. They sent us home with pills for vomiting and antibiotic pills and basicly said she needed to "toot" or burp and that it would work its self out. Wednesday she was walking some but wasn't drinking water and we don't remember seeing her urinate at all. Wednesday night around 9:30 pm she walked around a little and over an hour let out 3 large burps. I thought "ok, it's working it's way out". She still wouldn't take water so i gave her little bits with a medicine syringe. Around 11pm she literally collasped and vomited a small amount of brown gunk 3x. She was panting and shaking..My husband and I scooped her up and rushed to the vet. She went limp in my arms before we got there. The vet confirmed she was gone and asked if he could check her stomach because it was swollen said it would take about 10 min. Upon returning he said she had a small tear in her stomach. Please please tell me I did what I could for her? I am having a horrible time with this. They said she had "GAS".. We are watching our dachshund for any signs of depression. Its been very hard thinking if I had just taken her back to the vet earlier maybe they could have saved her. Thank you..

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