Updated September 25, 2026. Fact-checked against veterinary sources; review by a licensed veterinarian is in progress. See our editorial policy.
Quick answer: Dogs with long-lasting vomiting, diarrhea, or weight loss often have a chronic enteropathy, a long-term inflammation of the gut. Many of these dogs improve dramatically with a diet change alone, and they usually have an excellent outlook. Others need medication to calm the immune system. The outlook is more guarded when dogs lose protein through the gut (protein-losing enteropathy) or have intestinal cancer. A step-by-step workup helps find which group your dog is in.
Signs of chronic GI disease
- Diarrhea or vomiting lasting more than about 3 weeks, or coming and going
- Weight loss or poor coat
- Gurgling stomach, gas, or eating grass
- Changes in appetite
- Mucus or blood in stool
- Swollen belly or fluid buildup (with protein loss)
Common causes
- Food-responsive enteropathy: improves on a new diet. This is the most common type.
- Immune-mediated enteropathy (often called IBD): needs anti-inflammatory or immune-suppressing medication.
- Protein-losing enteropathy: the gut leaks protein, sometimes from dilated lymph vessels (lymphangiectasia).
- Parasites such as Giardia and worms.
- Pancreatic problems, including exocrine pancreatic insufficiency.
- Non-GI diseases such as Addison’s, liver, or kidney disease.
- Intestinal cancer, such as lymphoma.
How vets work it up
- Stool tests and deworming
- Bloodwork, including albumin (protein), cobalamin (vitamin B12), and tests for Addison’s and pancreatic disease
- Abdominal ultrasound
- A diet trial: a hydrolyzed or novel-protein diet fed strictly, with nothing else, for about 2–4 weeks for GI signs
- Endoscopy or surgical biopsies if diet trials don’t work or protein is low
Treatment
- Diet: the first step for most dogs. Many respond within 2 weeks.
- Vitamin B12 supplementation when levels are low.
- Fiber or probiotics for some dogs, especially with large-bowel diarrhea.
- Immune-suppressing medications such as prednisone, budesonide, or others, for dogs that don’t respond to diet.
- Low-fat diets for protein-losing enteropathy with lymphangiectasia.
- Antibiotics are now used much less often, only in specific situations.
Long-term outlook
- Food-responsive dogs usually do very well long term, as long as they stay on the right diet.
- Immune-mediated disease is usually controlled with medication, though some dogs have flare-ups.
- Low blood protein (albumin), low vitamin B12, and severe signs at diagnosis are linked to a more guarded outlook in studies.
- Intestinal lymphoma outlook depends on the type. Some forms respond well to treatment.
Home care
- Feed only the prescribed diet during trials, including treats and flavored medications.
- Keep a diary of stool quality, vomiting, appetite, and weight.
- Make diet changes gradually unless your vet says otherwise.
What to avoid
- Frequent diet switching, which makes it hard to know what works.
- Human anti-diarrhea medications without your vet’s guidance. Loperamide can be dangerous for some breeds (such as Collies) and in certain conditions.
- Leftover antibiotics, which can disrupt gut bacteria.
When to call your vet
Call promptly for blood in vomit or black stool, repeated vomiting, a swollen belly, lethargy, or rapid weight loss.
Frequently asked questions
Can dogs live a normal life with IBD?
Many do, with the right diet and medication.
How long should a diet trial last?
For GI signs, most dogs respond within 2–4 weeks if they’re going to.
Is chronic diarrhea in dogs serious?
It can be, especially with weight loss or low protein, but many causes are very treatable. A proper workup is key.
Sources
- Allenspach K, et al. Chronic enteropathies in dogs: evaluation of risk factors for negative outcome. J Vet Intern Med. 2007
- Dandrieux JRS. Inflammatory bowel disease versus chronic enteropathy in dogs: are they one and the same? J Small Anim Pract. 2016
- Merck Veterinary Manual: Inflammatory bowel disease in small animals
- Merck Veterinary Manual: Protein-losing enteropathy
This article is for general education and is not a substitute for care from your own veterinarian. Learn about The Pet Vet and our editorial policy.