Why Is My Cat Vomiting? Causes & When to Worry

Vomiting is one of the most common reasons cat owners call the vet. It can be something as simple as eating too fast — or a sign of serious disease. Knowing the difference is one of the most valuable skills a cat owner can develop.

Acute vs. Chronic Vomiting

Acute (sudden onset): Vomiting that starts suddenly in a previously healthy cat. Usually caused by dietary indiscretion, infection, or toxin exposure. Requires attention within 24-48 hours.

Chronic (ongoing): Vomiting more than 1-2 times per month over weeks or months. This is NOT normal and requires investigation. Common causes: IBD, food allergy, kidney disease, hyperthyroidism.

Common Causes of Vomiting in Cats

Dietary indiscretion: Eating something they shouldn't — spoiled food, plants, foreign objects. Usually self-limiting.

Hairballs: True hairballs ARE a form of vomiting. The cat hunches, retches, and produces a cylindrical mass of fur. More than 1-2 per month suggests over-grooming or GI disease.

Inflammatory Bowel Disease (IBD): One of the most common causes of chronic vomiting in cats. Requires dietary management and sometimes immunosuppressive therapy.

Food allergy: Unlike dogs, cats with food allergies often present with GI signs (vomiting, diarrhea) rather than skin issues.

Hyperthyroidism: The cat eats voraciously but loses weight, and often vomits.

Chronic kidney disease: Uremic toxins irritate the stomach lining causing intermittent vomiting.

Pancreatitis: Often presents as decreased appetite and lethargy rather than dramatic vomiting (unlike dogs).

Obstruction: Foreign body, tumor, or severe constipation/megacolon. Emergency — the cat cannot keep anything down.

When to Go to the Emergency Vet

Go now: Repeated vomiting (more than 3-4 times in a few hours), vomit containing blood (red or coffee-ground appearance), vomiting + lethargy together, known foreign body ingestion, vomiting + not eating for >24 hours.

Schedule a vet visit: Vomiting more than once a week, weight loss, change in appetite, increased thirst/urination alongside vomiting.

What Your Vet May Do

Blood work (CBC, chemistry, thyroid), abdominal X-rays or ultrasound, endoscopy or exploratory surgery for chronic cases, fecal testing for parasites, elimination diet trial for food allergy.

The Takeaway for Cat Owners

Occasional vomiting (once a month or less) with a cat that is otherwise eating, active, and maintaining weight may be monitored at home. Vomiting more than once or twice a month, vomiting with other signs (weight loss, lethargy, appetite change), or any vomiting that persists beyond 24 hours requires a vet visit.