Cats are experts at hiding discomfort. Unlike dogs, which may make it obvious when they are feeling unwell, cats often continue with their normal routines even when something is wrong.
That is why knowing your cat's normal behavior is so important. A small change in eating, drinking, grooming, sleeping, using the litter box or interacting with you can sometimes be an early indication of a health problem.
Not every unusual behavior means that your cat is sick. However, persistent or sudden changes deserve attention.
Here are some warning signs cat owners should never ignore.
1. A Sudden Change in Appetite
A cat that suddenly stops eating or eats considerably less than usual should be taken seriously.
Cats can lose their appetite for many reasons, including dental problems, gastrointestinal problems, pain, stress and other illnesses. Cats that refuse food for an extended period can develop additional health problems, so it is important not to simply assume that your cat is being picky.
An increase in appetite can also be significant, particularly when accompanied by weight loss or increased thirst.
If your cat's eating habits change noticeably, contact your veterinarian for advice.
2. Changes in Drinking or Urination
Pay attention to how much your cat drinks and how often it uses the litter box.
Increased thirst or urination can sometimes accompany conditions such as kidney disease or diabetes. Conversely, difficulty urinating can be an emergency, particularly in male cats.
Watch for:
Frequent trips to the litter box
Straining to urinate
Producing very little urine
Urinating outside the litter box
Blood in the urine
A sudden increase in drinking
A cat that is repeatedly straining to urinate but producing little or no urine needs urgent veterinary attention.
3. Vomiting or Diarrhea
Occasional vomiting can happen to cats, such as when they eat too quickly or cough up a hairball. However, repeated vomiting, persistent diarrhea or vomiting accompanied by other changes should not be ignored.
Contact your veterinarian if your cat has repeated episodes, appears weak or painful, refuses food or water, or develops other concerning symptoms.
Kittens, elderly cats and cats with existing health problems can be particularly vulnerable to dehydration.
4. Sudden Weight Loss or Weight Gain
Changes in body weight can be difficult to notice when you see your cat every day.
Try weighing your cat periodically, particularly if it is older or has a history of health problems.
Unexplained weight loss can accompany several medical conditions, while rapid weight gain can also indicate a problem.
If your cat's weight changes without an obvious explanation, discuss it with your veterinarian.
5. Hiding More Than Usual
Cats naturally enjoy quiet places and may occasionally disappear for a nap. But a cat that suddenly begins hiding much more than usual may be communicating that something is wrong.
Pain and illness can cause cats to become withdrawn.
Look at the bigger picture. Is your cat also eating less? Sleeping more? Avoiding interaction? Grooming differently? Using the litter box differently?
Several small changes occurring together can be more significant than any single behavior.
6. Changes in Grooming
Healthy cats usually spend a considerable amount of time grooming themselves.
A cat that suddenly stops grooming may be uncomfortable, ill or experiencing pain. Its coat may become greasy, tangled or generally unkempt.
On the other hand, excessive grooming can also be a warning sign. A cat may repeatedly lick one area because of pain, irritation, allergies or skin problems.
Look for bald patches, irritated skin, excessive scratching or persistent licking.
7. Breathing Problems
Changes in breathing should always be taken seriously.
Warning signs include:
Rapid breathing
Labored breathing
Breathing with the mouth open
Wheezing or unusual respiratory noises
Significant coughing
Difficulty breathing after only mild activity
Open-mouth breathing in a cat is not normal and requires prompt veterinary attention.
If your cat appears to be struggling to breathe, seek emergency veterinary care rather than waiting to see whether the problem improves.
8. Changes in the Eyes
Your cat's eyes can provide important clues about its health.
Watch for:
Redness
Swelling
Excessive tearing
Discharge
Squinting
Cloudiness
A visible change in the appearance of the eye
One pupil looking different from the other
Eye problems can sometimes deteriorate quickly, so unexplained changes should be evaluated by a veterinarian.
9. Changes in the Ears
Frequent scratching of the ears, head shaking, unpleasant odor, redness or dark discharge can indicate an ear problem.
Cats may develop ear mites, infections, allergies or other conditions affecting the ears.
Avoid putting household remedies or medications into your cat's ears unless your veterinarian recommends them. Some substances can make certain ear conditions worse.
10. Difficulty Walking or Jumping
Cats are remarkably good at hiding pain.
A cat that suddenly stops jumping onto furniture, has difficulty climbing stairs, walks stiffly or seems reluctant to move may be experiencing pain.
Older cats can develop arthritis, but reduced mobility should not automatically be dismissed as simply "getting old."
Other warning signs include limping, reluctance to be touched, unusual sleeping positions or becoming less active.
11. Unusual Vocalization
A change in your cat's voice or the amount it vocalizes can sometimes indicate a problem.
Some cats become unusually vocal when they are uncomfortable, while others become unusually quiet.
A sudden increase in meowing, crying, growling or other vocalizations deserves attention, especially if it occurs together with changes in appetite, mobility, litter-box habits or behavior.
12. Changes in the Litter Box
Because cats are creatures of habit, litter-box changes can be especially informative.
Be alert if your cat suddenly:
Stops using the litter box
Urinates in unusual places
Defecates outside the box
Visits the box unusually often
Strains
Produces unusually large or small amounts of urine
Has diarrhea or constipation
Has blood in the urine or stool
Do not assume that a cat is avoiding its litter box because it is "angry" or being difficult. Medical problems, pain, stress and litter-box issues can all cause changes in elimination behavior.
13. Bad Breath or Difficulty Eating
Persistent bad breath is not something that should simply be considered normal for cats.
Dental disease is common in cats and can cause bad breath, discomfort and difficulty eating.
You may notice your cat chewing differently, dropping food, preferring soft food or avoiding certain foods.
A veterinarian can examine your cat's mouth and determine whether dental treatment is necessary.
14. Sudden Personality Changes
You know your cat's personality better than anyone.
If a normally affectionate cat suddenly becomes withdrawn, or a calm cat becomes unusually aggressive, the change may have a physical or emotional cause.
Pain is one possible explanation, but environmental stress can also affect behavior.
The important thing is to notice a persistent change rather than assuming that your cat has simply developed a new personality.
When Is It an Emergency?
Some symptoms require immediate veterinary attention rather than waiting for a routine appointment.
Seek urgent veterinary care if your cat:
Has difficulty breathing
Is unconscious, extremely weak or unable to stand
Has seizures
Has severe or uncontrolled bleeding
Has suffered significant trauma
Is repeatedly straining to urinate without producing urine
Has severe or sudden pain
Has swallowed a potentially toxic substance
Suddenly develops severe neurological symptoms
When in doubt, call a veterinarian or emergency veterinary clinic and describe the symptoms.
Trust Your Knowledge of Your Cat
One of the most useful things you can do for your cat's health is simply to know what is normal for that individual animal.
How much does your cat normally eat? How often does it use the litter box? How active is it? How does it normally sleep? Does it enjoy being touched? How much does it groom?
When you know these patterns, changes become much easier to recognize.
Cats cannot tell us when something hurts, so their behavior often becomes our first clue.
A single unusual behavior may not mean that anything is seriously wrong. But a sudden or persistent change—especially several changes happening at the same time—is worth paying attention to.
And when your instincts tell you that your cat is not acting like itself, it is better to ask your veterinarian than to wait and hope the problem disappears.
