CATS · Symptom guide
Cat vomiting yellow foam: what real veterinary cases show
Yellow foam in a cat's vomit is bile. It usually means the stomach has been empty for a long stretch — often overnight — and stomach acid plus bile have built up enough to irritate the lining. This pattern (vomiting first thing in the morning, before breakfast) is so common that vets have a name for it: bilious vomiting syndrome.
But "common" doesn't mean "trivial". The same picture — yellow foam, morning vomiting, otherwise normal cat — shows up in published case series as the first sign of inflammatory bowel disease, chronic pancreatitis, food-responsive enteropathy, Helicobacter gastritis, and (in cats over ~8 years old) early hyperthyroidism or chronic kidney disease.
The cases below are real peer-reviewed reports from veterinary clinics around the world. Each one shows what the vet team actually did, what diagnostic moved the needle, and what treatment worked.
When to see a vet now
- Vomiting more than 2-3 times in one day, or for more than 48 hours.
- Refusing all food for more than 24 hours (cats can develop hepatic lipidosis fast).
- Blood in the vomit, or coffee-ground-looking material.
- Lethargy, hiding, or hunched posture between vomiting episodes.
- Any vomiting in a cat over 10 years old that's also losing weight.
Real cases from the veterinary literature
A teaser of peer-reviewed reports our semantic search surfaces for this complaint. Click into any case for the full abstract — or run a personalised search with your pet's exact details.
- A Case Report of Feline Cholangiohepatitis: Clinical Presentation and Diagnostic Work-Up
BIO Web of Conferences · 2026 · United States
An 8-year-old male Maine Coon cat weighing 4.1 kilograms was brought to the vet because he had yellowing of the skin and eyes (jaundice) and was constipated for over a week. He was very tired, not eating at all, and drinking less water than usual. Previous treatments to relieve his constipation didn't work, and tests showed he had low red blood cell counts and signs of liver pr
- Chronic Vomiting in Cats: Etiology and Diagnostic Testing.
Journal of the American Animal Hospital Association · 2016 · United States
Chronic vomiting in cats is a frequent issue that veterinarians encounter. When a cat is brought in for vomiting, it's important to tell the difference between vomiting and other problems like regurgitation or difficulty swallowing. There are many possible reasons for a cat to vomit regularly, so gathering a thorough history and conducting careful tests are essential to find th
- Chronic intermittent diarrhea in a 14-month-old Abyssinian cat.
The Canadian veterinary journal = La revue veterinaire canadienne · 2009 · Canada
A 14-month-old female Abyssinian cat was brought to the vet because she had been experiencing ongoing bouts of diarrhea and her mammary glands were swollen. The vet found that she had a type of intestinal infection caused by a parasite called Isospora felis, but the initial treatment didn’t help. Further testing revealed another infection caused by a different parasite, Tritric
- Feline Idiopathic Inflammatory Bowel Disease
Journal of Feline Medicine and Surgery · 2012 · United States
Feline idiopathic inflammatory bowel disease (IBD) is a condition in cats that causes ongoing problems in the digestive system, leading to symptoms like vomiting, diarrhea, and weight loss. This disease can affect any part of the gastrointestinal tract, especially the small intestine, and may also involve inflammation in other organs like the pancreas and liver, which can make
- Sclerosing eosinophilic extrahepatic cholangitis in a cat.
Journal of comparative pathology · 2025 · Brazil
A 9-year-old female cat was taken to the vet because she was losing weight, not eating, and had yellowing of her skin and eyes (jaundice). The vet found that she was in poor shape, had a low body temperature, and still showed signs of jaundice. Tests showed issues with her liver and bile ducts, and an ultrasound suggested inflammation in her liver and pancreas. Unfortunately, w
Frequently asked questions
- Why does my cat throw up yellow foam in the morning?
- Yellow foam is bile mixed with stomach acid. The most common cause is bilious vomiting syndrome — the stomach has been empty too long overnight, so acid and bile build up and irritate the lining. Splitting the daily food into more frequent smaller meals (including one right before bed) resolves it in many cats. Recurrent cases warrant a vet workup for IBD, pancreatitis, or Helicobacter.
- Is yellow vomit in cats an emergency?
- A single isolated episode in an otherwise bright, eating, drinking cat is usually not. Repeated episodes, vomiting with refusal to eat for >24h, weight loss, or blood are all reasons to call the vet today — especially in older cats, where chronic vomiting can be the first sign of hyperthyroidism, kidney disease, or alimentary lymphoma.
- What do vets test for first?
- Most workups start with a CBC, chemistry panel, total T4 (in cats over ~6 years), and abdominal ultrasound. Endoscopic biopsy is the gold-standard test for IBD and alimentary lymphoma when bloodwork is unremarkable. The case reports below show several real diagnostic pathways and their outcomes.