10 Signs Your Cat Is Sick (and When to Call the Vet)

Cats evolved as both predator and prey, so they instinctively mask weakness. By the time a cat looks obviously sick, the problem may have been building for days or weeks. That is why the earliest signs of illness in cats are usually small changes in routine, not dramatic symptoms.

This guide walks through ten warning signs, explains what each one can mean, and tells you how fast to act. It also covers the true emergencies that should never wait, and how to handle vet costs. It is general education, not a diagnosis. Your veterinarian is the only one who can tell you what is wrong with your cat.

Why Cats Hide Illness (and How to Notice Anyway)

In the wild, a visibly weak animal attracts predators. Your house cat still carries that wiring. A cat with a bad tooth, early kidney disease or arthritis may keep eating, purring and acting mostly normal for a long time.

The skill that helps most is knowing your cat's baseline. How much does she usually eat? Where does she sleep? How many times a day does she use the litter box? Illness almost always shows up as a change from normal, so you are looking for a pattern break, not a textbook symptom.

Sign 1: Hiding or withdrawing

A social cat who suddenly spends hours under the bed, in a closet, or behind the couch is telling you something. So is a cat who stops greeting you at the door, no longer sits in her favorite window, or becomes unusually clingy or irritable. Pain, fever, nausea and anxiety can all cause this.

One evening of hiding after visitors or a loud noise is normal. Hiding that lasts more than a day, or that comes with any other sign on this list, deserves a call to your vet.

A simple daily check

You do not need to be a clinician. A 60-second routine catches most problems early:

• Watch her eat. Does she approach the bowl eagerly, chew on both sides, drop food, or walk away after a few bites?
• Look at the litter box. Note the size and number of clumps, stool consistency, and any blood.
• Check the face. Eyes should be clear, nose free of crusts, and gums pink (not pale, yellow or bright red).
• Smell her breath. A strong foul odor can point to dental or kidney problems.
• Feel the body. Notice new lumps, a bony spine, or a tummy that seems larger or tender.

Write down anything unusual with dates. Notes like "ate half her dinner Tuesday and Wednesday" help your vet far more than "she seems off." Photos and short videos of limping, breathing or odd behavior are even better, since cats often act normal once they reach the clinic.

Appetite and Thirst Changes

Food and water habits are among the most reliable health indicators in cats. Both too little and too much deserve attention.

Sign 2: Eating less or stopping altogether

A cat who skips a meal because the weather changed or the food was new is not unusual. A cat who eats noticeably less for more than a day, or refuses food completely, needs a vet call. Cats are prone to a serious liver condition called hepatic lipidosis when they stop eating, and the risk is higher in cats who are overweight. Waiting several days to see if it passes is a gamble.

Common causes of appetite loss include dental pain, nausea, kidney disease, infections, constipation, stress and cancer. Some cats approach the bowl, sniff, and walk away. Others try to eat but drop food or chew on one side, which often points to mouth pain.

Do not force-feed at home or use human medications to stimulate appetite. Ask your vet what to do while you wait for the appointment.

Sign 3: Drinking and urinating more

Increased thirst is easy to miss in a multi-cat home, but there are clues. You may be refilling the water bowl more often, catching your cat at the faucet or sink, or finding larger-than-usual urine clumps in the litter box.

In cats, excessive thirst and urination are classic signs of conditions such as kidney disease, diabetes and hyperthyroidism, and these are especially common in middle-aged and senior cats. They are very treatable or manageable when caught early, and much harder when caught late.

The opposite problem: ravenous but thin

A cat who is suddenly always begging for food but losing weight is also a red flag. Hyperthyroidism and diabetes can both cause this combination. Many owners are happy to see a "hungry" older cat and do not realize it may be a symptom.

If you notice any appetite or thirst change that lasts more than a day or two, book an appointment. Bring a rough estimate of how much your cat eats and drinks, and mention any recent diet changes. Blood and urine tests are often the quickest way to find the cause.

Litter Box Warning Signs

The litter box is a daily health report, and many owners underuse it. Changes here often show up before anything else.

Sign 4: Changes in urination or stool habits

Watch for any of the following:

• Urinating outside the box, especially on cool surfaces like tile, a bathtub or a sink
• Frequent trips to the box with little or no urine produced
• Straining, crying or licking the genital area after urinating
• Blood in the urine (pink or red tint) or unusually strong smell
• Much larger clumps than usual, or none at all
• Constipation, with small, dry stools or repeated unproductive straining

Accidents outside the box are often assumed to be bad behavior. In reality, they are frequently medical. Urinary tract inflammation, bladder stones, infection, arthritis (making it hard to climb into the box) and kidney disease can all cause them. Punishing the cat makes things worse and delays treatment.

Important: a cat, especially a male, who is straining in the box and producing little or no urine may have a urinary blockage. That is a life-threatening emergency (see the emergency section below).

Using the box as a monitoring tool

Scoop at least once a day and pay attention to what you see. Using a litter that makes clumps easy to count and size can help. Some crystal litters, such as Pretty Litter Cat Litter, are marketed as changing color with certain urine changes. Treat that as a prompt to look closer and call your vet, not as a diagnosis.

If accidents have already happened, clean them thoroughly with an enzymatic or pet-specific odor remover such as Live Pee Free Pet Odor Eliminator. Cats return to spots that still smell like urine. Avoid ammonia-based cleaners, which can smell similar to urine to a cat.

Bring a fresh urine sample if your vet asks for one. Ask whether to use non-absorbent litter or a clean, dry container to collect it.

Vomiting, Diarrhea and Weight Changes

Digestive upsets are common in cats, but not all of them are harmless. The key is frequency, duration and what else is going on.

Sign 5: Vomiting

An occasional hairball is normal for many cats. But regular vomiting is not something to shrug off as "just what cats do." Call your vet if your cat:

• Vomits more than once or twice in a day
• Vomits several times a week or every week for a month
• Vomits and also refuses food or seems lethargic
• Vomits blood or material that looks like coffee grounds
• Cannot keep water down

Causes range from dietary changes and hairballs to pancreatitis, kidney disease, thyroid disease, inflammatory bowel disease and intestinal blockage. Repeated vomiting after playing with string, ribbon, hair ties or yarn is an emergency, because linear foreign bodies can damage the intestines.

Sign 6: Diarrhea or constipation

Soft stool for a day after a diet change may resolve on its own. Diarrhea lasting more than 24 to 48 hours, containing blood or mucus, or coming with vomiting, fever or lethargy needs a vet visit. Kittens, seniors and cats with other illnesses can dehydrate quickly.

Constipation matters too. A cat who strains repeatedly, passes small hard stools, or goes more than a day or two without defecating may have dehydration, pain or a more serious problem. Do not give over-the-counter laxatives or human medications unless your vet specifically instructs you to.

Sign 7: Unexplained weight loss or gain

Weight changes can be subtle on a fluffy cat. Feel along the spine and ribs every few weeks. A visible or palpable loss of muscle over the back and hips is a common sign in older cats with chronic disease.

Unplanned weight loss can accompany diabetes, hyperthyroidism, kidney disease, dental disease, digestive disease and cancer. Weight gain with a swollen belly is also worth investigating. If you are switching foods, such as moving to a fresh option like Nom Nom Fresh Cat Food, make the change gradually and track weight to separate diet effects from illness.

Breathing, Coat, Mouth and Mobility

Some of the most important signs of illness in cats are about how they look and move, not what they eat or excrete.

Sign 8: Breathing changes

Healthy cats breathe quietly and effortlessly. Watch for open-mouth breathing, panting (unlike dogs, cats rarely pant normally), wheezing, a hunched posture with elbows out, or a belly that heaves with each breath. A cough that sounds like retching or hacking can also signal asthma or heart or lung disease.

You can count resting breaths while your cat sleeps. Count each rise and fall of the chest over 30 seconds and double it. Vets generally want to hear about a sleeping or resting rate that is consistently above roughly 30 breaths per minute. Write the number down and mention it.

Labored breathing is an emergency, covered below.

Sign 9: A poor coat and grooming changes

Cats are fastidious groomers. A greasy, matted or scruffy coat often means the cat is too sick, sore or overweight to groom. Arthritis may make it hard to reach the lower back. Dandruff, hair loss, scabs, or overgrooming a spot until it is bald can mean skin disease, allergies, parasites, stress or pain.

Also check the mouth, eyes and nose:

• Bad breath, drooling, or dropping food may indicate dental disease, which is very common in cats
• Yellow gums or eyes can suggest liver trouble and need prompt attention
• Squinting, discharge or a visible third eyelid can point to eye or upper respiratory problems
• Frequent sneezing with discharge may be an upper respiratory infection

Sign 10: Lower activity and stiffness

Cats rarely limp dramatically. Instead, they stop jumping onto the bed, hesitate before the stairs, sleep more, play less, or sit in odd positions. Many owners write this off as aging. Osteoarthritis is very common in older cats and often goes undiagnosed, yet there are treatment and management options your vet can discuss.

Sudden lethargy, weakness, or a cat who will not get up is more urgent than a slow decline. If your cat seems to be in pain, flinches when touched, or cries out, call your vet the same day.

Emergency Signs: Do Not Wait

Most signs above warrant a call within a day or two. These do not. If you see any of the following, go to your vet or an emergency clinic immediately, and call ahead if you can.

Go now if your cat:

• Is straining to urinate or making repeated trips to the box with little or no urine. Male cats are at highest risk of urethral blockage, which can become fatal within a day or two. Crying, licking the genitals and vomiting often accompany it.
• Has labored breathing, breathes with an open mouth, has blue, gray or very pale gums, or is gasping.
• May have eaten a lily. All parts of true lilies and daylilies (including pollen and vase water) are considered highly toxic to cats and can cause acute kidney failure. Do not wait for symptoms. Treatment is most effective when started early.
• May have ingested another toxin, such as antifreeze, human pain relievers (acetaminophen, ibuprofen), dog flea products containing permethrin, rodent poison, or certain houseplants and essential oils.
• Has a seizure, collapses, or cannot stand or walk normally.
• Cannot use the back legs or cries out suddenly, which may signal a blood clot (more common in cats with heart disease).
• Has been hit by a car or fallen from a height, even if she seems fine, since internal injuries can be hidden.
• Vomits repeatedly, especially with a swollen abdomen, or you suspect a swallowed string.
• Has had no food or water for a day or more, or is severely lethargic or unresponsive.
• Is bleeding heavily or has a serious wound.

What to do on the way

Call the clinic so they can prepare. In a poisoning case, bring the product, plant or packaging, and note the time and amount. The ASPCA Animal Poison Control Center and Pet Poison Helpline are two commonly used hotlines (they typically charge a consultation fee). Do not induce vomiting or give home remedies unless a vet or poison expert tells you to.

Transport your cat in a secure carrier lined with a towel. Keep the car quiet and calm. A stressed, sick cat can bite or escape.

Vet Costs, Payment Options and Preparing for the Visit

Worrying about cost is one of the main reasons owners delay care, and delay often makes problems more expensive. Costs vary widely by region, clinic type and the problem involved, so ask for an estimate before agreeing to tests or treatment. Emergency and specialty hospitals generally cost more than regular daytime appointments.

Ways to manage the expense

• Pet insurance reimburses a portion of eligible costs after you pay. It usually excludes pre-existing conditions, so it works best when bought while your cat is young and healthy.
• Veterinary discount plans work differently. For example, the Pet Assure Veterinary Discount Plan is not insurance. Members pay a fee and receive discounted rates at participating practices, with no claim forms. Confirm that your vet participates and read what is covered before you sign up.
• Care financing and payment plans, offered by some clinics, can spread out a large bill. Read the terms and interest rules carefully.
• An emergency fund for your cat, even a small one built monthly, can reduce panic decisions.
• Ask your vet about options. Many cases have more than one reasonable path, such as phased diagnostics or different treatment tiers.

None of these replaces the others, and you should not wait for an emergency to compare them.

Getting the most from the appointment

Bring:

1. A list of symptoms with dates and any videos
2. The food brand, treats and supplements your cat gets
3. Any medications, with doses
4. A fresh stool or urine sample if requested
5. Your cat's vaccination and medical history if you are visiting a new clinic

Ask what the vet suspects, which tests are essential versus optional, what the likely cost is, and what signs would mean you should return sooner.

Finally, schedule regular checkups. Many vets recommend yearly exams for adult cats and more frequent visits for seniors. Routine bloodwork and a dental check are often where hidden illness first shows up.

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Frequently asked questions