Cat Health: How to Spot Illness Early and When to See a Vet
Key takeaways
- Cats hide illness well, so subtle changes in eating, drinking, litter habits, grooming, or activity are often the first sign something is wrong.
- Some signs are emergencies: difficulty breathing, straining to urinate with little or nothing produced, collapse, repeated vomiting, or a suspected poisoning all need a vet straight away.
- Routine preventive care, vaccinations, parasite control, dental care, and an annual check-up, prevents many problems and catches others early.
- When in doubt, call your vet; describing the change you've noticed over the phone is always better than waiting to see if it passes.
Cats are experts at hiding illness, so the first job of any owner is to notice the small changes. A cat that feels unwell will often simply do less, eat a little differently, or spend more time tucked away, long before anything dramatic happens. Learning your cat’s normal is the single most useful health skill you can have.
This is the hub for our Cat Health & Illness articles. Here is how to think about it.
Know your cat’s normal
You can only spot a change if you know the baseline. Pay attention to how much your cat normally eats and drinks, how often it uses the litter box and what’s in it, how active and playful it is, and how it grooms. Once you know what’s usual, a shift stands out.
Everyday signs a cat may be unwell
Any of these, especially if they last more than a day or two, are worth a vet’s attention:
- Eating or drinking noticeably more or less than usual
- Changes in the litter box: going more or less often, straining, or accidents
- Hiding more, or a drop in activity and playfulness
- A scruffy, ungroomed coat, or over-grooming one area
- Weight loss or gain
- Vomiting or diarrhoea that doesn’t settle quickly
Red flags: when it’s an emergency
Some signs mean you should contact a vet immediately, not wait and see:
- Difficulty breathing, or open-mouth breathing
- Straining to urinate with little or nothing produced, this is a life-threatening emergency, especially in male cats
- Collapse, extreme weakness, or seizures
- Repeated vomiting, or vomiting with obvious pain
- A suspected poisoning (see our note on foods and plants toxic to cats in the nutrition guide)
When you’re unsure whether something counts as an emergency, call your vet and describe what you’re seeing. They would always rather hear from you early.
Prevention is most of the job
A lot of cat health is about stopping problems before they start:
- Vaccinations and parasite control, kept up to date with your vet
- Dental care, since dental disease is common and painful but easy to miss
- A healthy weight, which protects the joints and lowers the risk of diabetes
- Annual check-ups (more often for kittens and senior cats), which catch quiet problems early
When to call your vet
The short version: when something has changed and stayed changed, or when you see any of the red flags above. You know your cat better than anyone, and that instinct that “something’s off” is worth acting on.
This guide is general information, not a diagnosis. Anything that worries you about your own cat should be checked by your vet, who can examine your cat and knows its history.
References
- Cornell Feline Health Center, Cornell University College of Veterinary Medicine.
- Feline Life Stage Guidelines, American Association of Feline Practitioners.
- Caring for your cat, International Cat Care.
Frequently asked questions
How do I know if my cat is sick?
Watch for changes from your cat's normal: eating or drinking more or less, changes in litter-box habits, hiding, reduced grooming or a scruffy coat, weight loss, vomiting or diarrhoea, or a drop in activity. Because cats mask illness, any persistent change is worth a vet's attention, even if your cat seems otherwise fine.
What are the signs a cat needs an emergency vet?
Get help immediately if your cat is struggling to breathe, straining in the litter box with little or no urine (especially a male cat), collapsed or unable to stand, vomiting repeatedly, bleeding heavily, having seizures, or may have eaten something toxic. These can become life-threatening within hours.
How often should a cat see a vet?
Most healthy adult cats benefit from a check-up at least once a year, kittens and senior cats more often. Annual visits keep vaccinations and parasite control up to date and let your vet catch problems like dental disease or weight change early.
Do cats hide when they are ill?
Yes. Cats are descended from solitary hunters and instinctively mask pain and illness, so they often seem fine until a problem is well advanced. That is exactly why owners are advised to act on subtle changes in eating, drinking, litter habits, grooming, or activity rather than waiting for obvious signs.
Can a sick cat get better on its own?
Minor upsets sometimes settle within a day, but because cats hide illness so well, anything that lasts more than about 24 to 48 hours, or comes with a red flag such as not eating, repeated vomiting, or straining to urinate, needs a vet. Waiting too long often lets a treatable problem become serious.
Written by Hannah Reeves. Reviewed by Dr Sarah Whitfield, BVSc MRCVS.
Our guides are written from personal experience and reviewed by a qualified veterinarian for accuracy. Read our editorial policy.