Why Is My Cat Vomiting? Hairballs, Diet & When to See the Vet
Vet-reviewed via PetHealth+ · Last reviewed June 2026
Common, usually mild causes
Hairballs — Cats swallow fur while grooming. Most passes through the gut; some comes back up as a sausage-shaped clump of fur and fluid. Long-haired breeds and heavy groomers are most affected. Regular brushing and hairball diets or gels can help.
Eating too fast — Some cats regurgitate undigested food soon after bolting a meal. Smaller, more frequent portions and puzzle feeders slow them down.
Diet change or rich food — A sudden switch or an unusual treat can upset a sensitive stomach. Transition foods over 7–10 days.
Grass or plants — Occasional plant nibbling may trigger vomiting; ensure houseplants are non-toxic (lilies are deadly to cats — see our toxic foods guide).
When vomiting may signal illness
Contact your vet if you notice:
- Vomiting more than once a week or daily
- Weight loss or poor appetite
- Blood in vomit (red or coffee-ground appearance)
- Lethargy, hiding, or behaviour change
- Diarrhoea at the same time
- A bloated or painful abdomen
- A male cat straining without producing urine (this can be a blocked bladder emergency)
Possible underlying causes include inflammatory bowel disease, food allergy, parasites, pancreatitis, kidney or liver disease, hyperthyroidism (common in older cats), and foreign-body obstruction.
What your vet may do
They will ask about diet, worming, and frequency, then examine your cat. Tests may include blood work, faecal checks, ultrasound, or imaging if a blockage is suspected. Treatment depends on the cause — from anti-nausea medication and a diet trial to treatment for a specific disease.
Practical tips at home
- Brush long-haired cats regularly
- Feed smaller meals from slow feeders
- Keep fresh water available
- Never give human medicines without veterinary advice
Related guides: Ringworm in cats · Indoor vs outdoor cats · Cat body language
Frequently asked questions
Is it normal for cats to vomit?
Occasional vomiting — especially hairballs — is common, but frequent vomiting (more than once a week) or any vomiting with other illness signs is not normal and needs a vet check.
How can I tell a hairball from something serious?
Hairballs usually produce a tubular mass of fur and happen intermittently in long-haired or heavy-grooming cats. Repeated vomiting, weight loss, or blood always needs investigation.
Should I change my cat's food if they vomit?
Only after ruling out illness with your vet. Sudden diet changes can themselves cause vomiting — transition slowly if a new food is recommended.
When is cat vomiting an emergency?
Seek urgent care for repeated vomiting, blood, lethargy, bloated painful abdomen, inability to keep water down, or if a male cat is straining in the litter box.