Chronic Vomiting in Cats: IBD, Hyperthyroidism, and Other Causes
Cats vomit. Everyone says so — but "they just do that" is not a diagnosis. Chronic vomiting in cats has real, identifiable, treatable causes. Here's how to tell them apart.
What you need to know
Vomiting once in a while is not unusual in cats. But vomiting weekly — or more — is not normal, and it is not something to simply accept. Chronic vomiting in cats is one of the most underreported and underinvestigated symptoms in feline medicine, largely because owners have been told for years that cats "just vomit."
The reality is that chronic or frequent vomiting in cats usually has an underlying cause — and many of those causes are diagnosable and manageable. The challenge is that several different conditions can look identical on the surface. Getting to the right answer requires a methodical veterinary approach.
Most veterinary internists consider vomiting that occurs more than once or twice per week, or has been ongoing for more than 3 weeks, to be chronic and worthy of investigation. Even if a cat seems otherwise well — eating, active, maintaining weight — frequent vomiting is a clinical sign that deserves attention, not normalization.
The most important causes to rule out
Inflammatory bowel disease (IBD)
Feline IBD is one of the most common causes of chronic vomiting in middle-aged to older cats. It involves persistent immune-mediated inflammation of the GI tract wall. Intestinal biopsy remains the gold standard for definitive diagnosis of feline IBD, though many veterinarians make a presumptive diagnosis based on clinical signs, bloodwork, and imaging. Cats with IBD may vomit intermittently for months or years before diagnosis, often with gradual weight loss and changes in appetite.
The most common form in cats is lymphocytic-plasmacytic enteritis. Importantly, feline IBD must be distinguished from GI lymphoma — the two conditions can look nearly identical clinically and even on ultrasound. Biopsy with histopathology remains the gold standard, and immunohistochemistry and/or clonality (PCR) testing may be used when appropriate to help distinguish them.
Hyperthyroidism
Hyperthyroidism — overproduction of thyroid hormone — is the most common hormonal disease in older cats, typically affecting those over 10 years. It causes a dramatically increased metabolic rate, and GI symptoms including vomiting, diarrhea, increased appetite with weight loss, and hyperactivity are all hallmarks. It is one of the most important conditions to rule out early because it is very treatable and because untreated hyperthyroidism causes serious cardiac complications.
Diagnosis is straightforward: a blood test measuring total T4 levels. If your older cat is vomiting and losing weight despite eating well, this should be tested at the first appointment.
Chronic kidney disease (CKD)
CKD is extremely common in older cats and frequently causes vomiting due to the buildup of uremic toxins that irritate the GI tract. Vomiting in a cat with CKD may be accompanied by reduced appetite, increased thirst and urination, weight loss, and lethargy. Bloodwork and urinalysis are required for diagnosis.
GI lymphoma
Feline GI lymphoma — particularly the low-grade (small cell) form — is one of the most common cancers in cats and can cause chronic vomiting that is clinically indistinguishable from IBD. Low-grade lymphoma in cats often responds well to treatment with chlorambucil and prednisolone, and many cats achieve prolonged remission. Biopsy is essential to distinguish it from IBD.
Food-responsive enteropathy
Some cats with chronic vomiting respond to a dietary elimination trial — suggesting a food-related component to their GI inflammation. As in dogs, this is diagnosed by response to a hydrolyzed or novel protein diet over 6–8 weeks, not by blood or saliva testing.
Pancreatitis and triaditis
Cats are unique in that they commonly develop concurrent inflammation of the pancreas, liver (cholangitis), and small intestine (IBD) simultaneously — a condition called triaditis. Vomiting, reduced appetite, and lethargy are typical. Diagnosis involves bloodwork, feline-specific pancreatic lipase (fPL), and ultrasound. See Guide 23 for more detail on feline pancreatitis and triaditis.
Other causes to consider
- Hairballs — True hairball vomiting is occasional and produces a tubular mass of hair; frequent retching without hairball production or frequent vomiting of food is not a hairball problem
- Foreign body obstruction — Linear foreign bodies (string, thread, ribbon) are a serious emergency in cats
- Constipation — Straining and nausea from constipation can cause vomiting in some cats
- Diabetes mellitus — GI symptoms can accompany feline diabetes
- Liver disease / hepatic lipidosis — Especially in cats that have stopped eating
Signs to watch for and track
- How often vomiting occurs — times per week or month
- When it happens — immediately after eating, hours later, or unrelated to meals
- What is vomited — food, bile (yellow fluid), hairballs, or other material
- Whether your cat's weight has changed — even small losses matter in cats
- Appetite changes — eating more or less than usual
- Thirst and urination changes — increased thirst may suggest hyperthyroidism or CKD
- Energy and behavior changes — hyperactivity (hyperthyroidism) or lethargy (CKD, lymphoma)
How vets investigate chronic vomiting in cats
A thorough workup typically includes:
- Full physical exam — Including palpation of the thyroid gland (enlarged in hyperthyroidism), abdominal palpation for masses or thickened bowel loops
- Bloodwork and urinalysis — Total T4 for hyperthyroidism, kidney values, liver enzymes, blood glucose, complete blood count
- Feline pancreatic lipase (fPL) — Specific test for feline pancreatitis
- Abdominal ultrasound — Evaluates GI wall thickness, layering, mesenteric lymph nodes, liver, pancreas, and kidneys
- Dietary elimination trial — 6–8 weeks on a hydrolyzed or novel protein diet if food-responsive disease is suspected
- Endoscopy and intestinal biopsy with histopathology — The gold standard for distinguishing IBD from GI lymphoma; immunohistochemistry and/or clonality testing may be added when appropriate
- Don't accept "cats just vomit" as a complete answer if your cat vomits weekly or more
- Request bloodwork including T4 for any cat over 8 years with vomiting — hyperthyroidism is common and easily tested
- Bring a written log of vomiting frequency, timing, and what was produced — this information significantly helps your vet
- If a dietary trial is recommended, follow it strictly — the same rules apply as in dogs (no unauthorized treats or foods)
- Ask specifically about distinguishing IBD from GI lymphoma if biopsy is recommended — the distinction matters enormously for treatment
When to contact your veterinarian urgently
- Vomiting more than 2–3 times in 24 hours
- Blood in vomit
- Complete food refusal for more than 24–48 hours — hepatic lipidosis can develop rapidly in cats that stop eating
- Significant lethargy or weakness
- Suspected ingestion of string, thread, ribbon, or other linear material — this is a surgical emergency
- Visible weight loss over a short period
- Distended or painful abdomen
Common myths
Myth: "Vomiting once a week is just normal for cats"
This is one of the most harmful misconceptions in feline medicine. Weekly vomiting is not a normal baseline — it is a clinical sign. Studies have found that many cats diagnosed with IBD or GI lymphoma had been vomiting "normally" for months to years before diagnosis. Chronic vomiting always warrants investigation, even in cats that otherwise seem well.
Myth: "It's probably just hairballs"
True hairball vomiting produces a cylindrical mass of hair, occurs occasionally, and is typically a discrete episode. Frequent vomiting of food, bile, or foam — even if a small amount of hair is present — is not explained by hairballs alone. Hairball remedies and high-fiber diets do not treat IBD, hyperthyroidism, or CKD.
- Vomiting more than once or twice a week is not normal in cats — it deserves investigation
- The most common causes of chronic feline vomiting include IBD, hyperthyroidism, CKD, GI lymphoma, and food-responsive disease
- Hyperthyroidism is extremely common in cats over 10 and is diagnosed with a simple T4 blood test
- IBD and GI lymphoma look clinically identical — biopsy with histopathology (with immunohistochemistry or clonality testing when appropriate) is the gold standard for distinguishing them
- Track vomiting frequency, timing, and content before your vet appointment — this data is genuinely useful
- Food refusal for more than 24–48 hours in a cat is a medical concern — hepatic lipidosis can develop quickly
- Never accept "cats just vomit" as a complete clinical answer
- Jergens AE, Crandell JM, Evans R, et al. A clinical index for disease activity in cats with chronic enteropathy. Journal of Veterinary Internal Medicine. 2010;24(5):1027–1033. doi.org/10.1111/j.1939-1676.2010.0549.x
- Vaske HH, Schermerhorn T, Armbrust L, Grauer GF. Diagnosis and management of feline hyperthyroidism: current perspectives. Veterinary Medicine: Research and Reports. 2014;5:85–96. doi.org/10.2147/VMRR.S39985
- Lingard AE, Briscoe K, Beatty JA, et al. Low-grade alimentary lymphoma: clinicopathological findings and response to treatment in 17 cases. Journal of Feline Medicine and Surgery. 2009;11(8):692–700. doi.org/10.1016/j.jfms.2009.05.021
- Norsworthy GD, et al. Prevalence and underlying causes of histologic abnormalities in cats suspected to have chronic small bowel disease. Journal of Veterinary Internal Medicine. 2013;27(4):814–818. doi.org/10.1111/jvim.12108
- Ettinger SJ, Feldman EC, Côté E, eds. Textbook of Veterinary Internal Medicine. 8th ed. Elsevier; 2017.
Last reviewed by PetGutHealth: June 2026
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