Pure fluid buildup in your dog’s abdomen is called “ascites.” The symptoms of ascites in dogs include vomiting, diarrhea, distended abdomen, difficulty breathing, pain if palpated, restlessness, and an inability to settle due to discomfort. Your dog may appear lethargic or weak. Specific symptoms can also be evident due to the underlying problem, such as increased drinking with kidney failure or coughing and weakness from heart failure. Many dogs will become reluctant to eat and will lose weight, although the scale may say the same number of pounds or even higher due to the retained fluid. Emergency Note for Ascites: If you notice your dog’s abdomen appears swollen, a veterinary appointment is the way to go. If you suspect bloat (see below), it is an emergency. If your dog is having trouble breathing, is suddenly weak, and/or has pale gums as well as a distended abdomen, that is also an emergency. Is Ascites in Dogs Serious? A buildup of belly fluid in your dog is a symptom of a serious condition, potentially organ failure. Protein loss via the intestines (protein losing enteropathy) or the kidneys (protein losing nephropathy) are two disease conditions that may cause ascites. Decreased albumin due to liver damage may also contribute. Trauma is another possible cause of ascites with blood from a ruptured spleen or urine due to damage to the bladder. With prompt surgical attention, the injuries can be repaired. Cancer causes include hemangiosarcoma with bleeding from the spleen or liver or rupture of a gastric tumor, causing peritonitis with inflammatory and infectious fluids accumulating. Certain toxins, such as rat poison, may lead to bloody ascites secondary to clotting problems. Ascites vs. Belly Fat in Your Dog True ascites tends to be gradual. You may miss it initially as the change slowly progresses. An overweight dog with a distended abdomen could have fat accumulation or possibly a loss of abdominal muscle tone as is seen in dogs with Cushing’s disease. In both cases, the distension is gradual. The abdomen feels firm but is not usually painful. This happens gradually. Ascites vs. Bloat in Your Dog If your dog is suffering from bloat—an extremely dangerous condition where the dog’s stomach fills with gas and can twist upon itself—he will be in obvious distress. Intense pain, pale gums, a rapid onset of swelling, and usually unproductive retching will be noted. This is an immediate medical emergency: Head for the nearest clinic, calling ahead, to let them know you are coming with a bloat case. Diagnosing the Cause of Ascites in Dogs The diagnosis will start with a complete physical examination and a thorough history. If your veterinarian suspects ascites due to your dog’s swollen belly, the next steps will be cytology by collecting a fluid sample to examine and imaging studies such as X-rays and/or an ultrasound. (When doing imaging, a large amount of fluid may obscure everything in the abdomen, or you may see the abdominal organs all pushe