Cats hide illness well. By the time something is obvious, it has often been developing for days. Knowing which signs need urgent action makes a real difference.
This is a guide, not a substitute for veterinary advice. If your cat is unwell and you are unsure, always call your vet or an emergency line. They would rather hear from you than not.
Emergency: call now
These signs need a vet call immediately — do not wait to see if they improve.
Difficulty breathing, open-mouth breathing, or breathing with the neck extended
Straining to urinate with little or no urine produced (especially in male cats)
Sudden paralysis or inability to use the back legs
Severe injury: bleeding that does not stop, suspected broken bones, burns
Suspected ingestion of string, thread, tinsel, or a foreign object
Call within 24 hours
These are not immediate emergencies in most cases, but should not be left until a routine appointment that is days away.
No food eaten for more than 24 hours
Vomiting more than twice in a day, or blood in vomit
Diarrhoea with blood, or lasting more than 24 hours
Sudden lameness or reluctance to put weight on a limb
Eye discharge that is coloured (yellow or green), or a visible eye injury
Swelling anywhere on the body, particularly the face or limbs
Rapid or unexplained weight loss over one to two weeks
Hiding and lethargy for more than 24 hours with no obvious cause
Monitor, but call if it gets worse
These changes are worth watching. If they persist beyond 48 hours, or if more signs appear, call your vet.
One episode of vomiting with no other signs in an otherwise well cat
Sneezing two or three times a day (may be normal; persistent sneezing is not)
A slightly reduced appetite that resolves within 24 hours
Loose stools without blood that resolve in 24 hours
Mild lethargy after a stressful event (house move, new pet, visitor)
When in doubt, ring first. Most UK vet practices offer a nurse triage phone line. Many will tell you within minutes whether your cat needs to come in immediately, within hours, or can wait for the next appointment. The call is free and fast.
Finding out-of-hours care
All UK vet practices are legally required to provide or refer to 24-hour emergency care. Your vet's answering machine should have a number for out-of-hours. Save it before you need it.
My cat is hiding more than usual — should I be worried?
A cat that suddenly hides much more than normal, especially combined with reduced eating or drinking, is showing a classic sign of illness. Cats instinctively hide weakness. If hiding has persisted for more than 24 hours with any other change, call your vet.
How do I know if my cat is in pain?
Cats mask pain well. Signs include: not grooming, hunching over the litter box, flinching when touched in one area, a changed facial expression (squinting, flattened ears), reluctance to jump, and vocalisation when handled. If you suspect pain, call your vet — do not give human painkillers, which are toxic to cats.
My cat has not eaten for one day. Is that an emergency?
One day without food in an adult cat is concerning but not always an emergency. Two days without food in a cat that is also hiding, vomiting, or lethargic is an emergency. In obese cats, even 48 hours of anorexia can trigger hepatic lipidosis. When in doubt, call.
What if my cat is straining to urinate?
This is an emergency, especially in male cats. A blocked bladder is life-threatening and can be fatal within 24–48 hours. If your cat is making repeated trips to the litter box with little or no urine produced, call an emergency vet immediately.
How often should a healthy cat see a vet?
Once a year for cats under seven, twice a year for cats seven and older. Senior cats develop conditions that progress quickly, and twice-yearly checks can catch changes before they become serious.