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10 Signs Your Cat Is Sick and Needs a Vet

Cats are masters at concealing illness — a survival instinct inherited from their wild ancestors who could not afford to show weakness. This makes it especially challenging for owners to recognise when something is wrong. By the time obvious symptoms appear, many conditions are already significantly advanced. Knowing the subtle early signs can make all the difference.

Why Cats Hide Illness

The tendency to mask pain and illness is deeply ingrained in cats. Unlike dogs — which often vocalise or seek attention when unwell — cats are more likely to hide, reduce activity, and withdraw when they feel ill. This behaviour, shaped by millions of years of evolution as both predator and prey, means that by the time a cat shows obvious signs of illness, the condition has often been developing for some time.

The PDSA and RCVS both emphasise that subtle behavioural changes are often the earliest indicators of illness in cats. Owners who know their cat well are uniquely positioned to notice when something is 'off' — even if they cannot identify exactly what. If your instinct tells you something is wrong, it almost certainly is worth a veterinary opinion.

Regular handling and observation are therefore an important part of cat ownership. Cats that are handled regularly from kittenhood are easier to examine and are more likely to tolerate veterinary assessments. A monthly at-home check — running your hands gently over the body to feel for lumps, sore areas, or changes in body condition — is a simple habit that can catch problems early.

The 10 Key Signs Your Cat Is Sick

The following signs warrant a veterinary assessment, particularly if new, persistent, or accompanied by other changes. 1. Changes in appetite — eating significantly more or less than usual. Both increased and decreased appetite can indicate disease. 2. Weight loss or gain — gradual unexplained weight change is one of the most sensitive indicators of underlying illness. 3. Changes in water consumption — drinking more (and urinating more) can indicate diabetes, kidney disease, or hyperthyroidism. 4. Changes in litter tray habits — straining, blood in urine or faeces, going outside the tray, or changes in frequency or consistency of stools. 5. Vomiting or regurgitation — occasional vomiting of hairballs is normal, but frequent or persistent vomiting is not.

6. Changes in coat quality — a dull, matted, or neglected coat often indicates the cat has stopped grooming, which itself suggests illness, pain, or obesity. 7. Hiding or withdrawal — a cat that previously sought out company becoming reclusive is a significant red flag. 8. Breathing changes — rapid, laboured, or open-mouth breathing in a cat is always an emergency. 9. Lethargy and reduced activity — a cat sleeping significantly more than usual, or showing reduced interest in play and interaction. 10. Vocalisation changes — increased crying or yowling (particularly at night) can indicate pain, hyperthyroidism, hypertension, or cognitive decline in older cats.

Signs That Require Emergency Veterinary Care

Some signs require immediate emergency veterinary attention — do not wait for a routine appointment. These include: any breathing difficulty or open-mouth breathing (cats should never breathe through their mouths when at rest); inability to urinate, or straining to urinate with no output (possible urinary blockage, which is life-threatening in male cats); collapse, extreme weakness, or inability to stand; seizures or loss of consciousness; obvious trauma from a road accident or fall; uncontrolled bleeding; and a pale, white, blue, or grey gum colour (indicates serious cardiovascular or shock-related emergency).

Out-of-hours emergency vet consultations in the UK cost £200–£350 on average. If your cat needs emergency care, never delay due to cost concerns — urinary blockages, in particular, can be fatal within 24–48 hours without treatment. Contact your emergency vet or out-of-hours service immediately.

For non-emergency concerning signs — changes in appetite, weight, or behaviour — a routine appointment is appropriate, but do not delay more than 1–2 days if symptoms persist or worsen.

Regular Health Checks: Prevention and Early Detection

Annual or 6-monthly vet health checks are the best complement to home monitoring. Annual checks allow your vet to assess body condition, dental health, heart and lung function, and discuss any concerns. For cats over seven (considered senior), 6-monthly checks are recommended, as conditions such as kidney disease, hyperthyroidism, and dental disease become increasingly common.

A routine health check and annual vaccination consultation typically costs £40–£65 in the UK. Blood tests and urine analysis, recommended annually for cats over eight, add £80–£150 but can detect kidney disease, diabetes, and hyperthyroidism at subclinical stages — when treatment is most effective.

The cost of early detection is almost always less than the cost of treating advanced disease. Early-stage chronic kidney disease managed with diet and medication is a very different proposition — both clinically and financially — from end-stage kidney failure requiring intensive support.

Finding a Vet That Explains Costs Clearly

One barrier to seeking veterinary care is uncertainty about cost. Many UK cat owners delay seeking advice because they are unsure how much a consultation will cost and fear being hit with a large bill. The March 2026 CMA reforms have significantly improved this — vets are now required to publish standard price lists, making it easier to know what to expect before you walk through the door.

CompareMyVet at app.comparemyvet.uk helps UK cat owners compare local vet practices based on published prices. Our platform currently covers Brighton & Hove with 29 practices, and is expanding across the UK. Knowing your local vet's consultation fee in advance removes one barrier to seeking timely care.

If your cat is diagnosed with a condition requiring long-term medication, ask your vet for a written prescription. Under the March 2026 CMA reforms, prescription fees are capped at £21, and purchasing medication from a registered online pharmacy can save 40–60% on ongoing costs — money that can be better spent on ensuring your cat gets proper monitoring.