How to Tell if Your Cat Is Sick

Cats are masters at hiding when they’re not feeling well, which can make it tough to know when something’s wrong. But paying attention to small changes like appetite, behavior, or grooming habits can reveal early signs of illness. This guide covers the most common symptoms to watch for, how to care for a sick cat at home, when to seek emergency help, and how to be prepared before a crisis hits. Whether you're dealing with a mild bug or something more serious, knowing what to look for can help you act quickly and give your cat the care they need.

Key Takeaways

• Changes in your cat’s appetite, behavior, grooming, litter box use, or body language can all be subtle cries for help. Catching these signs early can make a huge difference in your cat’s health.

• Support your cat with hydration, rest, and a calm environment, but never ignore serious symptoms like difficulty breathing, collapse, or not eating for over 24 hours. When in doubt, always call your vet.

• Always be prepared before an emergency. Research emergency vets in advance, track your cat’s symptoms daily if they’re sick, and avoid risky home remedies. Quick action and preparation save lives.

Common Signs Your Cat Might Be Sick

Appetite changes or refusal to eat

Loss of appetite, eating significantly more or less than usual, or changes in water consumption can signal various health issues.

Unusual lethargy or lack of activity

If your cat is sleeping a lot more than usual, seems weak, or isn’t interested in playing or moving around, it could be a sign they’re not feeling well.

Vomiting, diarrhea, or other digestive symptoms

While occasional hairballs are normal, frequent vomiting, dry heaving, or signs of nausea could mean an underlying illness.

Weight loss or gain without a clear reason

Rapid weight loss or gain, unkempt or greasy coat, visible lumps or bumps, or changes in posture can indicate health problems.

Increased hiding or antisocial behavior

Hiding more than usual, increased aggression, excessive vocalization, or sudden changes in social behavior often indicate discomfort or illness.

Behavioral Red Flags and Body Language Clues

Sick cat body language: hunched posture, pinned ears, dilated pupils

If your cat is hunching up, keeping their ears pinned back, or has wide, dilated pupils even in normal light, it could be a sign they’re not feeling great. A hunched posture might mean their tummy or joints hurt, pinned ears can show they’re scared or uncomfortable, and big pupils could be a clue they’re in pain or really stressed out. If you notice these signs sticking around, it’s a good idea to check in with your vet.

Cat acting weird: sudden clinginess, aggression, or confusion

If your normally independent cat suddenly won’t leave your side or constantly wants attention, they might be feeling sick or anxious. On the flip side, if your usually friendly kitty is hiding or avoiding people, that’s also a red flag. Watch out for unexpected aggression too. Hissing, swatting, or biting can be a cat’s way of saying they’re in pain, especially if they’re normally calm. And if your cat seems confused, gets lost in familiar places, or just seems “off,” it could point to something more serious like a neurological issue or illness.

Overgrooming, hair loss, or poor coat condition

If your cat is licking or chewing so much that they’re losing fur or creating bald spots, it could be a sign of allergies, stress, or something like fleas or a skin issue. Patchy hair loss or a thinning coat can also point to infections, hormonal problems, or overgrooming from anxiety. And if their fur starts looking dull, greasy, matted, or just messy, it might mean they’re not feeling well enough to groom themselves properly.

Vocal changes: excessive meowing, yowling, or silence

If your cat starts meowing more than usual—especially with a sad or distressed tone—it could mean they’re in pain, confused, or trying to tell you something’s wrong. Loud, drawn-out yowling (especially at night) is often a sign of serious discomfort or disorientation, and it's common in older cats with cognitive issues. If your normally chatty cat suddenly goes quiet, they might be feeling too sick or weak to speak up. Either way, changes in vocal habits are worth paying attention to.

Litter box issues: urinating outside the box, constipation, blood in urine

If your cat suddenly starts peeing outside the litter box, it’s not just bad behavior. It could be a sign of a urinary tract infection, kidney issues, arthritis, or stress. Constipation is another red flag; if they’re straining, passing tiny hard stools, or haven’t gone in a few days, something could be seriously wrong. And if you ever see blood in their urine—even a pinkish tint—it’s a medical emergency. Don’t wait to call the vet. 

If medical problems are ruled out and your cat’s just a bit picky about their litter, Boxie® Glo™ offers a natural, comfy litter box experience they’re more likely to enjoy. Shop here.

Signs That Require Immediate Veterinary Attention

My cat is not eating or drinking and very weak

Complete loss of appetite combined with weakness is extremely serious in cats. Unlike dogs, cats can develop hepatic lipidosis (fatty liver disease) within just 2-3 days of not eating. When combined with weakness and lethargy, this indicates severe illness, dehydration, or organ failure that requires immediate intervention.

Seizures, collapse, or disorientation

Any seizure activity, sudden collapse, or severe disorientation represents a neurological emergency. Seizures can indicate poisoning, brain tumors, metabolic disorders, or other serious conditions. Even if your cat seems to recover quickly, these episodes require immediate evaluation to prevent potentially fatal complications.

Open-mouth breathing or labored breath

Cats should never breathe with their mouths open unless extremely stressed or overheated. Open-mouth breathing, rapid breathing, or visible effort to breathe indicates respiratory distress, heart failure, or other life-threatening conditions. This is always an emergency requiring immediate oxygen support and treatment.

Yellow, pale, or blue gums

Normal cat gums should be pink. Yellow gums indicate liver problems or severe anemia, pale gums suggest blood loss or shock, and blue or gray gums signal oxygen deprivation. All of these color changes represent serious systemic problems requiring emergency treatment.

Unresponsive or extreme lethargy

A cat that won't respond to their name, touch, or favorite treats, or one that seems barely conscious, is experiencing a medical crisis. This level of unresponsiveness can indicate severe dehydration, organ failure, poisoning, or other life-threatening conditions.

How to Tell if Your Cat Has a Fever

Physical signs of fever without a thermometer

If your cat has a fever, you might notice signs like warm ears or paw pads, tiredness, lack of appetite, and less interest in drinking water. They may shiver, breathe faster, seek out warm spots, or seem “off” and less active than usual. Signs of dehydration like sticky gums or skin that doesn’t bounce back can also show up, so it’s important to look at the full picture and check with a vet if anything seems wrong.

How to take a cat’s temperature at home

Taking your cat’s temperature rectally is the most accurate method. You’ll need a digital pet thermometer, some lubricant, and treats for afterward. Gently hold or wrap your cat in a towel, lubricate the tip, and insert it about an inch into the rectum, holding it steady for about a minute. Always be gentle—if your cat gets too stressed, it’s best to stop and ask a vet for help. While ear thermometers made for pets are an option, they’re not as reliable, and forehead ones don’t work well on cats.

What causes fever in cats

Fever in cats can be caused by a variety of things. Infections like respiratory issues, UTIs, or abscesses are the most common. Inflammatory conditions, such as IBD or pancreatitis, can also cause a fever. A mild fever after vaccines is normal and usually goes away in a day or two. Other causes include certain cancers, especially blood-related ones, as well as stress, overheating, medications, or exposure to toxins.

When to seek veterinary care

If your cat’s temperature goes over 104°F or drops below 99°F, it’s a serious red flag and needs immediate vet care. A fever lasting more than a day—especially with symptoms like vomiting, diarrhea, or trouble breathing—is also cause for concern. Cats that seem really tired, stop eating, or show other unusual signs should be checked out, and this is especially important for kittens or senior cats, who are more at risk for complications.

What not to do: common home remedy mistakes

Never give your cat human meds like Tylenol, ibuprofen, or aspirin—they’re highly toxic and can be deadly. Avoid using alcohol rubs or cold baths to bring down a fever, as these can do more harm than good. Always keep fresh water available, even if your cat isn't eating, and skip home remedies unless your vet says otherwise. Cats can go downhill fast, so if you’re unsure or symptoms persist, it’s best to call your vet sooner rather than later.

Most Common Cat Illnesses and Their Symptoms

Upper respiratory infections

Upper respiratory infections are super common in cats, especially those from shelters, multi-cat homes, or who spend time outdoors. They’re usually viral but can include bacteria too. Common signs include sneezing, runny nose, watery or crusty eyes, and a mild fever. Some cats may eat less if they can’t smell their food. 

More serious symptoms like mouth breathing, extreme tiredness, or dehydration need prompt attention. While many cases clear up on their own, infections that last more than a week or get worse can lead to bigger issues like pneumonia or chronic sinus trouble, so don’t wait to call your vet if things aren’t improving.

Diabetes and kidney disease

Diabetes and kidney disease are becoming more common in middle-aged and senior cats. Signs of diabetes include drinking and peeing a lot, eating more but losing weight, feeling tired, and sometimes having sweet-smelling breath or weak back legs. Kidney disease can look similar but may also involve vomiting, bad breath (like ammonia), mouth sores, and dehydration. Since both cause increased thirst and urination, only a vet can tell them apart with proper tests. Early diagnosis and regular care make a big difference in keeping your cat feeling their best.

Hyperthyroidism

Hyperthyroidism is a common hormonal issue in older cats, usually caused by overactive thyroid glands due to benign tumors. Cats with this condition often eat a lot but still lose weight, act hyper or restless, meow more, and drink and pee more than usual. You might also notice a fast heartbeat, messy coat, vomiting, or even a lump in their neck. Calm cats can become edgy or aggressive, and their sleep habits may shift. If left untreated, it can lead to serious heart problems—but the good news is, it’s very treatable when caught early.

Parasites and internal infections

Parasites are common in cats, especially those who go outside or interact with other animals. Intestinal parasites can cause diarrhea, vomiting, weight loss, a bloated belly, or even visible worms in the stool. External parasites like fleas lead to lots of scratching, hair loss, and skin irritation, while ear mites cause dark gunk in the ears and constant head shaking. Internal infections vary but might include fever, tiredness, appetite loss, or bathroom changes. The good news? Most parasites are easy to treat if caught early, and regular prevention helps keep your cat (and your household) safe.

Feline leukemia and FIV

Feline Leukemia (FeLV) and Feline Immunodeficiency Virus (FIV) are viral infections that weaken a cat’s immune system and need lifelong management. FeLV can cause weight loss, pale gums, recurring infections, and even cancer or anemia, while FIV—often called feline AIDS—leads to slow-developing symptoms like dental issues, poor healing, and frequent respiratory infections. Though there’s no cure, cats with these viruses can still live happy lives with regular vet care, indoor living, and quick treatment for any illness. FeLV vaccines are available, and since both viruses spread mostly through close contact or fighting, keeping your cat indoors is a great way to help prevent them.

How to Care for a Sick Cat at Home (When Appropriate)

Keeping your cat hydrated and comfortable

To help a sick cat feel better at home, make sure they have fresh water in a few spots around the house. Some cats even prefer running water, so a pet fountain can help. Offer small, warm meals of easy-to-digest food, and try different textures or flavors if they’re not eating (just don’t force-feed without your vet’s okay). 

Set up cozy, quiet resting spots with soft bedding that are easy to reach, especially if your cat has trouble moving. Keep them warm with blankets or a low-heat heating pad, but make sure they can move away if they get too hot. And if they’re not grooming themselves, gently help out with a soft brush or damp cloth if they’re comfortable with it.

Isolating from other pets

If your cat is sick with something contagious, it’s a good idea to keep them in a separate room with their own litter box, food, water, and cozy bedding. Even if the illness isn’t contagious, a quiet space away from other pets can help reduce stress and give them a better chance to rest and recover. Isolation also makes it easier to monitor how much they’re eating, drinking, and using the litter box. Just be sure to wash your hands before and after handling your sick cat, and change clothes if needed to avoid spreading anything to other pets.

Creating a stress-free recovery environment

To help your sick cat feel safe and comfortable, keep the household calm. Limit noise, stick to routines, and avoid visitors or big changes. Have the same people care for your cat to reduce stress, and keep familiar items like their favorite blanket or toy nearby for comfort. Avoid strong smells from cleaners or air fresheners that might bother them. Interact gently and let your cat decide how much attention they want. Also, make sure the litter box is easy to reach, especially if your cat isn’t moving much, and keep it extra clean since sick cats can be picky about hygiene. Check out our blog post here on how to keep the litter box extra clean.

Monitoring progress and journaling symptoms

Keeping a daily log of your cat’s symptoms can really help with recovery. Track things like how much they eat, drink, pee, and poop, along with their energy level and any changes you notice. If your vet asks you to take their temperature, jot down the reading and the time. Make note of any shifts in behavior or how they’re responding to treatment—both good and bad. Keep a record of all medications, including dosage, time given, and any reactions. Photos of things like skin issues or eye discharge can be super helpful, too. Share all this info with your vet to help guide the best care.

Knowing when home care is no longer enough

If your cat’s symptoms get worse, new issues pop up, or they’re not improving as expected, reach out to your vet right away. Emergency signs like trouble breathing, collapsing, or seizures need immediate care no matter the treatment plan. If your cat won’t take meds, has a bad reaction, or you’re struggling to give them properly, call your vet for help instead of skipping doses. Not eating for more than 24 hours or signs of dehydration are also serious. And if you ever feel unsure or overwhelmed, trust your gut. It’s always okay to ask your vet for guidance.

When and How to Find Emergency Vet Care

What symptoms require urgent attention

If your cat is having trouble breathing, collapses, has a seizure, is unresponsive, bleeding heavily, or may have been poisoned, get to an emergency vet right away. Same-day care is also critical for things like straining to pee (especially male cats), nonstop vomiting, bloody diarrhea, extreme pain, a bloated belly, or pale or discolored gums. Fevers over 104°F or temperatures under 99°F are also urgent. If your cat’s been in an accident, like a fall or dog attack, get them checked even if they seem okay. Internal injuries aren’t always obvious. And for pregnant cats, problems during labor or heavy bleeding are emergencies, too.

How to prepare for an emergency vet visit

Before an emergency happens, look up nearby emergency vets, save their contact info in your phone, and keep it posted near your regular vet’s number. Know where they are and how long waits usually are, and keep a basic pet first aid kit handy. 

If a crisis hits, call the clinic on your way to let them know what’s going on—they can prep and guide you over the phone. Always use a secure carrier, even if your cat seems calm, and if they’re seriously hurt or unconscious, gently transport them on a towel or board with minimal handling. Bring any medical records, meds, or vaccine info you have, and if poisoning is suspected, bring the packaging. Keep in mind that emergency visits can be pricey, so it’s good to know payment options ahead of time, especially if you have pet insurance or need a payment plan.

Using online vet services and telehealth options

Telehealth can be a helpful option for minor issues, follow-ups, medication questions, or when you’re unsure if your cat needs an in-person visit. It’s great for things like behavior concerns or mild symptoms. But virtual care can’t replace a hands-on exam, lab tests, or imaging—so it’s not right for emergencies or anything serious. Platforms like Vetster and Fuzzy offer 24/7 access to licensed vets, though costs and availability vary by state. For virtual visits, make sure you have good lighting, a strong internet connection, your cat’s medical history, and any photos or videos of symptoms. Just remember: if it’s a real emergency, skip telehealth and head straight to the vet.

Here are some top-rated telehealth veterinary services we recommend:

1. Vetster

Best for: 24/7 access and prescription services

Features: Connects pet owners with licensed veterinarians via video, chat, or phone. Offers prescription services where legally permitted.

Pricing: Appointments start at $50; annual unlimited access available for $137.88.

2. Pawp

Best for: Emergency coverage and multiple pets

Features: Provides 24/7 chat and video consultations. Includes a $3,000 emergency fund for life-threatening situations.

Pricing: $99/year for membership; additional $19/month for emergency fund access.

3. Chewy Connect With a Vet

Best for: Budget-conscious pet owners

Features: Free live chat for Chewy customers; $19.99 for 20-minute video calls. Offers advice but does not prescribe medications.

Availability: Available from 6 AM to midnight ET; not available in all states.

What to expect in terms of cost and timing

Emergency vet visits can be pricey. Basic exams often run $150–$500, and more serious cases can climb into the thousands depending on what tests, treatments, or hospital stays are needed. Costs vary based on how serious the issue is, what time it is (nights and weekends cost more), and where you live. Since emergency clinics use a triage system, expect to wait if your cat isn’t in critical condition. Most places expect payment upfront, so bring a credit card or check if they accept CareCredit, offer payment plans, or work with pet insurance. If you have insurance, you’ll usually need to pay first and get reimbursed later, so it’s a good idea to know what your plan covers ahead of time.

Tips for identifying trusted vets in your area

Don’t wait for a crisis to find emergency vet care. Do your research while your cat is healthy so you’re not scrambling under pressure. Look for clinics with AAHA accreditation and board-certified vets, and check for clean facilities, up-to-date equipment, and services like X-rays, lab testing, and overnight monitoring. Read reviews and ask around for recommendations, but focus on overall trends, not one-off complaints. Some clinics offer tours, so you can get a feel for the space and staff ahead of time. Make sure they’re upfront about costs, explain treatment options clearly, and communicate well. It also helps if they coordinate smoothly with your regular vet. Finally, consider how close the clinic is to your home and whether it’s open 24/7 or only during certain hours. Being prepared means faster, better care for your cat when it matters most.

Frequently Asked Questions 

What are the warning signs your cat is crying for help?

Cats are great at hiding pain, so even small changes can be big red flags. Look for things like a sudden change in appetite, lethargy, hiding more than usual, excessive vocalization (or sudden silence), aggressive behavior, or unusual litter box habits like peeing outside the box. Body language also tells you a lot. Pinned ears, a hunched posture, and wide pupils can all mean something’s wrong. If your cat seems “off” in any way and it doesn’t go away quickly, it’s worth checking with your vet.

How can you tell if a cat has a fever without a thermometer?

While a thermometer is the only way to be sure, there are signs to watch for. Warm ears or paw pads, shivering, loss of appetite, increased sleep, and seeking out warm spots could all point to a fever. You might also notice faster breathing or signs of dehydration like sticky gums or skin that doesn’t bounce back when gently pinched. If several of these signs show up together, it's time to consult your vet.

How to treat a sick cat without going to the vet?

For mild illnesses or during recovery, keep your cat hydrated by offering fresh water in multiple spots. Some cats prefer fountains or a little broth added to their bowl. Serve small, warm meals that are easy to digest, and offer quiet, comfy spaces to rest. Keep things calm and stress-free, and gently help with grooming if needed. But always monitor symptoms closely. If your cat’s not improving, stops eating, or shows serious signs (like vomiting, difficulty breathing, or extreme weakness), you need to get veterinary help right away.

What are symptoms of a sick cat’s eyes?

Sick cats may have watery, crusty, or red eyes—common signs of upper respiratory infections or conjunctivitis. You might also see discharge (clear or colored), swelling around the eyelids, or signs of discomfort like pawing at the face or squinting. Infections involving the eyes can get worse quickly, so if these symptoms last more than a day or two, contact your vet.

How to know if your cat is dying?

Some signs that a cat may be nearing the end include extreme lethargy, no interest in food or water, difficulty breathing, pale or blue gums, and being unresponsive to voice or touch. They may hide or seem disoriented. It’s heartbreaking, but if you’re seeing these symptoms, it’s time to speak with a vet right away. They can help determine what’s happening and guide you through what your cat needs, whether it’s treatment or comfort-focused care.

What causes sudden fever in cats?

Fevers in cats are usually caused by infections—respiratory, urinary, or abscesses are common culprits. Inflammatory conditions like IBD or pancreatitis can also trigger a fever, as can stress, certain medications, or exposure to toxins. In rare cases, fever may be related to cancer. A mild fever after vaccination is normal and usually goes away on its own. But if the fever is high, lasts more than a day, or comes with other concerning symptoms, see your vet.

What home remedies can help with mild illness?

For minor issues, encourage hydration by offering water in multiple places or mixing a little low-sodium broth into their bowl. Offer warm, soft food in small amounts and try different textures or flavors to tempt picky eaters. Keep the environment calm, quiet, and cozy, and help with gentle grooming if your cat isn’t up to it. Just be careful—skip home remedies like human medications or alcohol rubs, which can be harmful. Always check with your vet before trying anything new.

When is it okay to wait and monitor vs. act immediately?

It’s okay to wait and monitor if your cat has mild symptoms like sneezing, a slightly reduced appetite, or seems a little less active—but only for a short time. You should act immediately if your cat is having trouble breathing, collapses, has a seizure, stops eating or drinking for over 24 hours, or shows signs like pale gums, blood in urine, or severe vomiting. If you’re ever unsure, trust your gut—it’s always safer to call your vet and ask.