Why Is My Cat Vomiting

This page is educational reference material for preparing questions. A licensed veterinarian examines the animal, makes the diagnosis, and sets the treatment.

Cat vomiting causes: hairballs, dietary issues, poisoning, kidney disease, and pancreatitis. Occasional vs chronic vomiting.

Vomiting in Cats Is Not Normal — Even If It's Frequent

The single most common misconception brought into feline practice is that cats simply are vomiters. They are not. The 2022 AAFP consensus on chronic enteropathy and a long-running series of papers from Cornell Feline Health Center make the same point: a cat vomiting more than once or twice a month has a problem that deserves a diagnosis. Most of those cats have low-grade chronic inflammation (inflammatory bowel disease, IBD), and a meaningful subset have small-cell gastrointestinal lymphoma — a distinction that takes full-thickness biopsy or endoscopy to make but that genuinely changes prognosis.

The first job in any vomiting workup is to distinguish the three patterns that owners lump together:

• Regurgitation — undigested food tubed out without abdominal effort, often seconds to minutes after eating. Points toward oesophageal disease, not stomach disease.
• True vomiting — rhythmic abdominal contractions, drooling, and often a warning yowl; content is partially digested, bile-tinged, or foamy.
• Hairball expulsion — a trichobezoar, cylindrical, mostly fur. One or two per month in a long-haired cat is within normal bounds; weekly is not.

Eight Causes That Account for Most Feline Vomiting

Hairballs and dietary intolerance

The fur ball every few weeks in a grooming-heavy cat (Persian, Maine Coon, Ragdoll) usually needs nothing beyond brushing and a hairball-formula or higher-fibre food. If fur balls become weekly, the problem is rarely hair — it is altered GI motility from underlying inflammation.

Food sensitivity or abrupt diet change

Cats are notoriously intolerant of food changes beyond about 10% a day. A 7–14 day transition and a single novel-protein trial (hydrolysed or limited-ingredient) for 6–8 weeks is the diagnostic test — not a supplement.

Inflammatory bowel disease (IBD)

Chronic intermittent vomiting, soft stool, weight loss over months, hunger preserved. Cornell Feline Health Center describes this as the single most common cause of chronic vomiting in cats over five. Diagnosis is histopathology via endoscopy or full-thickness biopsy; treatment ranges from diet trials through immunosuppression.

Small-cell GI lymphoma

Indistinguishable from IBD on clinical signs alone. PARR (PCR for antigen receptor rearrangement) and histopathology separate them. Prognosis with chlorambucil and prednisolone is surprisingly good — a median survival often 2–3 years.

Chronic kidney disease

Affects roughly 1 in 3 cats over 10 and 1 in 2 over 15 (International Renal Interest Society, IRIS). Nausea comes from uraemia; vomiting is often the sign that brings the cat in. Maropitant and an SDMA on the next blood panel are the standard moves.

Hyperthyroidism

A cat over 10 with weight loss, a ravenous appetite, vomiting, and a faster-than-expected heart rate — total T4 is the screening test. About 10% will be euthyroid on T4 alone and need free T4 or a T3 suppression test.

Pancreatitis

Feline pancreatitis is usually a quiet, chronic, smouldering disease — not the dramatic high-fat-meal picture you see in dogs. fPL and abdominal ultrasound are the best diagnostics; it often accompanies IBD and cholangitis (the feline "triaditis").

Foreign body, especially linear

String, thread, tinsel, hair ties, sewing elastic, ribbon. Always lift the tongue: a string anchored under the tongue with intestines plicating distally is an emergency laparotomy. Do not pull a visible string — it can lacerate the bowel.

Red-Flag Scenarios by Age

• Kitten under 6 months: roundworms, panleukopenia (parvovirus of the cat), FIP, toxin ingestion, intussusception. A vomiting kitten is an emergency until proven otherwise.
• Young adult (1–6 years): foreign body, FIV/FeLV-related disease, asthma-associated coughing misread as vomiting, hyperthyroidism (rare but rising in middle age).
• Middle-aged (7–11 years): CKD, IBD, hyperthyroidism, pancreatitis, diabetes mellitus with ketoacidosis.
• Senior (12+): CKD is the default hypothesis. Lymphoma, hyperthyroidism, and heart disease climb the list. Dental disease is a frequently missed cause of nausea in this age group.

Home Observation — The First 24 Hours

Useful cats are the ones you have already measured against a known baseline. Build the baseline before the next episode if you can.

1. Photograph or video an episode if safely possible — vets often cannot tell regurgitation from vomiting from a verbal description alone.
2. Note content: food, foam, yellow bile, blood, hair, string, grass. Bile-only morning vomiting often points to bilious vomiting syndrome — sometimes fixed by a small late-night snack.
3. Water intake — measure it in millilitres for a day. Normal is ~50–60 mL/kg/day. Anything over 100 mL/kg is a polydipsia finding.
4. Litter box output — frequency, urine clump size, stool form. A cat producing grapefruit-size urine clumps is polyuric.
5. Weight — weigh yourself, then weigh yourself holding the cat. A loss of more than 5% of body weight in a month is flagged by the AAHA as clinically significant.
6. Eating and grooming — a cat that has stopped grooming is feeling worse than one that has not.
7. Environment — new plants (lilies are the classic emergency), new cleaning product, new food, a move, a new pet, guests, construction noise.

What Not to Do

• Withhold food for longer than 24 hours. A cat that fasts too long develops hepatic lipidosis. If your cat has not eaten for 24 hours, this is a call — not a "let's see tomorrow."
• Give any human medication. Paracetamol (Tylenol) is lethal to cats even at a single tablet. Aspirin, ibuprofen, and Pepto-Bismol are also dangerous. Famotidine and omeprazole have veterinary uses but only under a vet's direction.
• Free-feed raw meat or home-cooked food without planning. Salmonellosis and nutritional imbalance are common on poorly planned home diets.
• Use hairball gel daily without a diagnosis. Petroleum-based laxatives can reduce fat-soluble vitamin absorption over time.
• Assume a stressed cat. Stress vomiting exists but is a diagnosis of exclusion in veterinary medicine, not a first guess.

The Vet Visit: What Actually Happens

A structured chronic-vomiting workup from a general practitioner usually proceeds as follows. Knowing the sequence helps you budget rather than being surprised.

• Full exam with thyroid palpation, abdominal palpation, oral exam, and body condition score.
• Senior/sick-cat profile: CBC, chemistry, total T4, SDMA, urinalysis, faecal. Catches hyperthyroidism, CKD, diabetes, liver disease, anaemia, parasites.
• Abdominal radiographs: for obstruction, megacolon, masses, radiopaque foreign material.
• Abdominal ultrasound: sensitive for intestinal wall layering changes in IBD/lymphoma, pancreatitis, mesenteric lymph nodes, masses, ureterolithiasis.
• fPL (feline pancreatic lipase) and cobalamin/folate: separates pancreatitis and small-intestinal malabsorption.
• Endoscopy or exploratory with full-thickness biopsies: the only way to distinguish IBD from small-cell lymphoma with confidence.
• Infectious screening where risk exists: FeLV/FIV for outdoor or multi-cat homes, Toxoplasma in certain presentations.

US Cost Ranges (2026)

• Exam with nausea treatment and fluids under the skin: $120–$260
• Senior cat profile (CBC, chemistry, T4, urinalysis, SDMA): $220–$420
• Two-view abdominal radiographs: $150–$300
• Abdominal ultrasound by radiologist: $450–$850
• fPL, cobalamin, folate bundle: $180–$340
• Inpatient fluids and anti-emetics for 24 hours: $450–$1,100
• Endoscopy with biopsies and histopathology: $1,400–$2,800
• Exploratory laparotomy for foreign body: $2,200–$4,800
• Radioactive iodine (I-131) for hyperthyroidism, inpatient: $1,300–$2,400 (one-time, curative in roughly 95% of cases)
• Chlorambucil and prednisolone for small-cell lymphoma, monthly: $70–$180

Breed and Age Modifiers

• Siamese, Oriental, Tonkinese: higher reported rate of IBD and lymphoma.
• Maine Coon, Ragdoll, Persian, Norwegian Forest, Birman: hair burden drives mechanical hairball vomiting, but chronic vomiting in these breeds should not be dismissed as "just grooming."
• Abyssinian, Somali: predisposed to pyruvate kinase deficiency; renal amyloidosis reported in some lines — atypical vomiting in a young Abyssinian deserves a fuller chemistry panel.
• Sphynx, Bengal, Savannah: higher observed rates of HCM — cardiac disease can present with vague appetite loss and intermittent vomiting.
• Burmese: diabetes mellitus is overrepresented.
• Senior domestic shorthair (12+): the statistical default is CKD until proven otherwise.

Common Owner Mistakes

• Treating hairballs empirically for a year. Chronic hair-ball-sounding vomit in a 14-year-old cat is CKD or lymphoma more often than it is hair.
• Letting a not-eating cat fast "to settle the stomach." Hepatic lipidosis sets up inside 24–72 hours in an overweight adult cat.
• Changing food every week. Churns the gut and masks the pattern. Pick a diet, stay on it for 6–8 weeks, and write down the result.
• Administering Tylenol or aspirin. Tylenol is fatal to cats. This single mistake still causes multiple ER deaths each year.
• Pulling a visible string. Under-tongue or anal strings anchor an intestinal plication. Seek surgery, not tugging.
• Assuming the blood work "was fine last year." Feline CKD and hyperthyroidism can move from normal to clinically obvious in six months.

Sensible Prevention

• Keep lilies (true lilies, daylilies, Easter lilies) out of the house entirely. All parts are nephrotoxic.
• Annual senior labs from age 8 as a minimum cadence. Screening is how subclinical CKD is caught early enough to extend life by years (Cornell Feline Health Center).
• Brushing a long-haired cat 2–3 times a week reduces trichobezoars far more than any oral gel.
• Secure sewing supplies, ribbon, tinsel, hair ties, and rubber bands as if they were medications.
• Clean water in wide, shallow bowls away from food stations. Cats drink less when water is next to food; under-drinking drives CKD progression.

Related Symptom Guides

Chronic vomiting rarely stands alone in a feline workup. These guides cover the symptoms that typically cluster with it.

• Why Is My Cat Not Eating? — the 24-hour liver-disease clock
• Why Is My Cat Losing Weight? — the top-three feline differentials over 10
• Why Is My Cat Drinking So Much Water? — polydipsia patterns in cats
• Why Does My Cat Keep Throwing Up Hairballs? — when "hair" is the wrong answer
• Why Is My Cat Lethargic? — separating quiet from unwell

Should I go to the emergency vet?

A reasonable grasp of this territory makes every other decision easier — and specific quirks matter more than any generic profile.

How much will treatment cost?

A cat that vomits more than a single hairball, or that vomits and then hides, needs an exam. The costs often include an anti-nausea injection, bloodwork, and films if a foreign body or a blockage is possible. Hairballs that are actually asthma will not show up on a diet change alone.

Can I treat this at home?

Pick up food for a few hours only if the cat just vomited once and is still bright, then offer a small meal. A string under the tongue, repeated vomiting, or a male cat also straining in the box means go in. Do not give a human nausea syrup.