If your cat is acting differently and you’re trying to figure out what’s wrong, the most useful thing you can do is learn to read the specific signs cats give when they’re sick. Cats are exceptionally good at hiding illness, so by the time you notice something is off, it’s worth paying close attention. While no online tool replaces a veterinary exam, understanding what to look for, and how urgent it is, helps you make the right call.
Why Cats Are Hard to Diagnose at Home
Cats instinctively mask pain and illness. In the wild, showing weakness makes an animal a target, and domestic cats still carry that programming. Any physical illness will change your cat’s attitude and behavior, but the changes can be subtle: sleeping in a different spot, eating a little less, grooming less frequently, or quietly withdrawing from the household. These shifts are easy to dismiss as moodiness, but they’re often the earliest signs of a real problem.
Researchers have identified five facial cues that reliably indicate pain in cats: ear position (ears flattened or rotated outward), tightening around the eyes, tension in the muzzle, whisker position changes, and a lowered head. If your cat’s face looks “off” to you, especially with squinted eyes and ears pulled to the sides, pain is a likely explanation.
Symptoms You Can Check Right Now
Breathing
A healthy cat at rest takes 15 to 30 breaths per minute. Count your cat’s breaths while they’re relaxed or sleeping. If they’re consistently above 35 breaths per minute, that’s a concern. Cats in respiratory distress rarely make noise about it. Instead, they stretch their neck out, lie on their chest with elbows splayed to the sides, or simply hide. Open-mouth breathing in a cat that hasn’t just been playing is always abnormal.
Hydration
Gently pinch the skin between your cat’s shoulder blades and lift it straight up, then release. In a well-hydrated cat, the skin snaps back into place immediately. If it settles slowly or stays tented for a moment, your cat is likely dehydrated. Pale, dry, or tacky gums are another warning sign. Dehydration accompanies many feline illnesses and makes them worse quickly.
Litter Box Habits
Changes in urination or defecation are some of the most telling signs. A cat visiting the litter box repeatedly without producing urine, crying while straining, licking at their genital area, or urinating outside the box may have a urinary blockage. This is especially dangerous in male cats. A blocked urethra can cause kidney failure and become fatal within two to three days without treatment. If your male cat is straining to urinate and producing nothing, that is an emergency right now, not something to monitor overnight.
Vomiting
The occasional hairball or isolated episode of vomiting isn’t unusual. What matters is the pattern. Frequent acute vomiting, vomiting large volumes, or vomit that contains blood or smells unusually foul warrants prompt attention. If your cat vomits and then seems fine, it’s reasonable to monitor for 24 hours. But if vomiting continues past that point, your cat stops eating, becomes lethargic, or develops diarrhea on top of it, don’t wait longer than 48 hours before getting them seen.
Intermittent vomiting that comes and goes over weeks often points to a chronic condition like inflammatory bowel disease, liver problems, or even gastrointestinal tumors, particularly in older cats. A cat that “has always been a puker” may actually have a treatable condition that’s been slowly progressing.
Appetite and Weight
A cat that stops eating entirely for more than 24 hours needs attention, because cats are uniquely prone to a dangerous liver condition when they go without food for too long. On the other end, a cat eating ravenously while losing weight is a classic presentation of hyperthyroidism, the most common hormonal disorder in middle-aged and older cats. Other signs include increased thirst, more frequent urination, vomiting, diarrhea, and an unkempt coat. Hyperthyroidism and chronic kidney disease frequently occur together in aging cats, so these symptoms in a senior cat (roughly 10 years and older) deserve bloodwork.
Behavioral Red Flags
Sometimes the only symptom is a change in behavior. Watch for these patterns:
- Hiding more than usual. A cat that suddenly spends all day under the bed or in a closet is often in pain or feeling unwell.
- Reduced grooming. A coat that looks greasy, matted, or unkempt suggests your cat doesn’t feel well enough to maintain it.
- Loss of interest. A normally social cat that stops greeting you, stops playing, or stops jumping to favorite spots may be dealing with pain, weakness, or general malaise.
- Increased vocalization. Some cats in pain or confusion will meow more than normal, especially at night. In older cats, this can signal cognitive decline, hyperthyroidism, or high blood pressure.
None of these behaviors on their own confirm a specific diagnosis, but any persistent change from your cat’s normal baseline is worth investigating. You know your cat’s personality. Trust what feels different.
Balance and Coordination Problems
A cat that suddenly tilts its head to one side, falls or leans in one direction, walks in circles, or has eyes that flick rapidly back and forth likely has a vestibular problem, essentially a disruption in the inner ear or the brain’s balance center. This can look alarming, and some cats will vomit during the acute phase. Vestibular disease has many possible causes, from ear infections to more serious neurological conditions.
A different pattern, where the cat walks with exaggerated, high-stepping movements, sways when standing still, or has a tremor that worsens when reaching for food, points to a cerebellar issue. In kittens, this is often cerebellar hypoplasia, a condition present from birth that doesn’t get worse over time. In adult cats with a sudden onset, it needs investigation.
Household Dangers That Mimic Illness
If your cat’s symptoms appeared suddenly, consider whether they may have been exposed to something toxic. Lilies are one of the most dangerous household plants for cats. Every part of the plant is poisonous, including the pollen. The first signs are vomiting, depression, and loss of appetite, typically within two hours of exposure. A cat may then seem to briefly improve as the gastrointestinal symptoms fade, but acute kidney failure develops within 24 to 72 hours. Without treatment, lily poisoning is fatal within three to seven days.
Common human medications are another major risk. Acetaminophen (Tylenol), ibuprofen, and aspirin are all lethal to cats at doses that would be safe for a person. If there’s any chance your cat chewed on a pill, a medication wrapper, or a plant, mention it when you call the vet. That information can change the treatment plan entirely.
True Emergencies: Don’t Wait
Some situations require an immediate trip to an emergency vet, not a “let’s see how they are in the morning” approach:
- Straining to urinate with no output, especially in male cats
- Collapse or inability to stand
- Severe bleeding, whether from a wound, in vomit, or in stool
- Difficulty breathing, with neck extended or mouth open
- Seizures lasting longer than five minutes, or multiple seizures in a row
- Sudden loss of coordination or responsiveness
- Known ingestion of a toxic substance
A single seizure that stops within a couple of minutes and after which your cat recovers fully is not an emergency on its own, but it does warrant a veterinary visit soon. Repeated seizures, prolonged seizures, or any seizure following head trauma is a different story.
What to Track Before Your Vet Visit
If you’ve decided your cat needs to be seen but the situation isn’t immediately life-threatening, gathering details beforehand makes the appointment far more productive. Note when the symptoms started, how often they’re happening, and whether they’re getting worse. If your cat is vomiting, pay attention to what the vomit looks like (food, bile, foam, blood) and how soon after eating it happens. For litter box issues, note frequency, output, and any changes in color or consistency.
Take a short video of any symptom that’s intermittent, like episodes of wobbling, unusual breathing, or straining in the litter box. Cats have a well-earned reputation for appearing perfectly healthy the moment they arrive at the clinic, and a video gives your vet something concrete to evaluate.