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6 Secret Signs of a Sick Cat

By Colleen Williams
published: May 5, 2017 - updated: March 22, 2022 • 6 min. read
Sick Kitten 640x420

Key Takeaways

  • It’s not always easy to tell if cats have an illness or injury, but there are signs if you know where to look.
  • Any dramatic change in behavior can be a sign of a problem; be especially alert to vomiting, diarrhea, loss of appetite, weight loss, and/or lethargy.
  • Other signs of trouble include hiding, changes in litter box behavior, hair loss, and bad breath.

Cats are notorious for their fickle nature; affection is only on their terms. It can be difficult to detect when your pet is sick, as many initial symptoms are subtle. Add to this the fact that most felines aren’t too keen on pet parents invading their personal space and it can be downright impossible to discern an illness early.

Ain’t Doin’ Right:

ADR is a catch-all term used by vets that means “ain’t doin’ right.” Say these three little letters to your veterinarian and they’ll know your cat is acting funny, ill, or hurt, but you’re not sure of the cause.

Symptoms include anything that is out of the ordinary: vomiting, diarrhea, loss of appetite, weight loss, and/or lethargy. The phrase ain’t doin’ right is actually a little misleading because there definitely is something going on for your vet to find.

Distinguishing between typical cat behavior and signs of sickness comes down to sudden changes. Behaviors that may be normal in one pet are unusual in another if they appear abruptly. It’s best to err on the side of caution when it comes to your pet’s health. Veterinarians are more than happy to answer any questions you have about potential symptoms, so feel free to call your local clinic before bringing your cat in – we know cat carrier wrangling can be a daunting task!

1. Hiding

sick cat
It’s normal for cats to snooze in hidey holes like the linen closet, but a sick feline may completely avoid humans. (

An ill feline may become secretive, camping out in a favorite hidey hole: under the bed or couch, in a cubby, or on a bookshelf. This instinct to hide allows a sick animal to conserve energy and recuperate faster as well as avoid potential enemies in their weakened, vulnerable state. If you haven’t seen your pet for a while, scout out their usual household hangouts. Search high and low – but usually high – as well as behind furniture and hanging objects, like curtains and clothes.

Some cats are very human-averse, comfortable only with a lucky few. Be mindful of your pet’s personality before assuming the worst; newly adopted cats in particular can be skittish, almost invisible as they stealthily assess their environment. However, if a typically social feline becomes withdrawn and cranky, it may be time to call the vet.


2. Changes in Defecation

kitten litter box
Pets leave important clues about their health in the litter box! Pay attention to any changes in potty habits. (

Pay attention when scooping the litter box. These gross yet necessary observations can help you detect changes in your cat’s health early. If you find yourself with nothing to scoop, your pet is most likely constipated. This often indicates an intestinal obstruction caused by a hairball or other ingested object; tumors, medications and dehydration can also cause this symptom, so visit your vet to receive a definitive diagnosis.

On the opposite end of the spectrum, diarrhea is a sign of dozens of medical conditions. Food allergies, intolerances and poisoning; intestinal parasites; gastroenteritis; and many chronic diseases can all cause diarrhea in cats. Pro tip – when scheduling your pet’s vet appointment, be sure to ask if they require a stool sample for testing!

3. Loss of Appetite

cat food
Cat got your appetite? Going without food for even 24 hours can be dangerous for felines and their delicate livers. (via

You may not consciously notice how much your cat is eating, depending on your method of feeding. Leaving a bowl out to top off daily may be the most convenient way to keep Fluffy fed, but it makes measuring kibble consumption almost impossible. It’s important to keep track of your pet’s appetite, as eating more or less is an indicator of illness.

You’re most likely overfeeding your cat, another reason measuring exact portions of food is essential. A veterinarian is best qualified to determine portion size and frequency, which varies according to age and any chronic health conditions, like diabetes or food allergies. If your cat hasn’t eaten for 24 hours, visit the vet! Fatty liver disease is a dangerous, fast-acting consequence of appetite loss in cats. Feline livers are not efficient at processing fats, leading to a buildup of fat when the starvation process begins. If the disease is too advanced, hospitalization may be required to ensure the cat receives appropriate nutrition.

4. Lethargy

kitten sleeping
While it’s normal for cats to sleep up to 20 hours per day, visit the vet if your pet is basically hibernating. (

Just a fancy word for fatigue, this difference in your cat’s energy level points to something wrong. While the average feline sleeps 15 to 20 hours daily, catnapping all day may be an energy-conserving behavior related to illness. A playful kitten or sassy senior who goes all Sleeping Beauty needs to visit the vet to break the spell. There’s a difference between lazy and lethargic: if your cat is alert enough to be annoyed, he or she may just have a stubborn streak.

Avoiding exercise and activity in general can also indicate pain in pets, particularly seniors. Arthritis and traumatic joint injuries are some of the most common causes of joint pain in cats. Other symptoms that often accompany lethargy include fever, loss of appetite, avoidance, and coughing. If your pet seems excessively sleepy or withdrawn for more than 48 hours, make an appointment with your vet. While the common kitty cold can cause fatigue and typically goes away on its own, it can easily be mistaken for more serious medical conditions.

5. Hair Loss

cat cone of shame
Cat hair loss is commonly caused by excessive itching. An e-collar or -cone is often used to allow wounds to heal. (

Officially known as alopecia, a cat losing hair is oftentimes related to stress or anxiety. The extent of the hair loss ranges from thinning, patchy fur to completely bald spots. While seasonal shedding is natural, unusual or abrupt coat changes are not, especially if the effects are uneven. Excessive grooming or scratching can also lead to hair loss in cats and may be prompted by an irritant like food ingredients, fleas, or ear mites. Look to see if your pet is itching any particular spot, which can provide hints as to the underlying cause. Itching around the ears is a symptom of ear mites, while full-body involvement often points to allergies.

Trim your cat’s claws to prevent a painfully itchy feline from injuring itself. Any nicks and scratches in the skin can potentially become infected, a secondary condition that may require antibiotics or minor surgery. Vets often recommend an Elizabethan or e-collar – also known as the “cone of shame” – while wounds are healing. Most felines fully regrow their fur, but hold off on intense grooming during recovery.

6. Really Bad Breath

cat bad breath
If your little lion has some serious dragon breath, try brushing your cat’s teeth daily, which also prevents dental disease. (

While it’s usually canines who could use a breath mint, occasionally cats suffer from halitosis. Dental issues are typically at the root of the problem; plaque and tartar build up on teeth, attracting bacteria. Periodontal diseases like gingivitis requires professional teeth cleaning that can be pricey, up to $1,000 depending on the health and age of the cat – motivation enough to brush your cat’s teeth.

Keep kitty’s chompers squeaky clean by brushing regularly! According to Dr. Heather Oxford of California Animal Rehabilitation (CARE), every other day is ideal. Work up to this frequency by first getting your cat used to you touching the outside and, eventually, inside of the mouth. Select a flavorful toothpaste for cats – no human brands! – and pick a toothbrush that’s size-appropriate.

However, there are other types of “bad” breath that indicate more serious medical conditions. A cat’s breath won’t ever be minty fresh; it should smell faintly fishy, like the main ingredient in your food of choice. Sweet-smelling breath is a hallmark of diabetes in cats, while a urine-like odor commonly results from kidney disease. Seniors may suffer from chronic bad breath, which is treatable through regular teeth brushing with enzymatic toothpaste.

Diagnosis and Treatment

Moving away from generic diagnoses is a huge step in vet care. Much like the care we receive from doctors, vets want to get to the bottom of every mysterious illness. Vets now have a myriad of tests they can rely on to properly diagnose and treat.

Pet Parent Tip: It’s perfectly fine to go into your vet’s office with vague symptoms; as a pet parent, you know when something just isn’t right. Costs can include everything from tests to treatment, ranging from $40 to possibly thousands.

The content is not intended to be a substitute for professional veterinarian advice, diagnosis, or treatment. Always seek the advice of your veterinarian or other qualified health provider with any questions you may have regarding a medical diagnosis, condition, or treatment options.

colleen williams
By Colleen Williams

Over the past decade, Colleen has written about health, wellness, beauty, and even pets for The New York Times, The Cut, Refinery29, xoVain, Healthy Paws Pet Insurance, and Seattle Met Magazine, as well as many beauty brands. She has a BFA in Art History from the University of New Mexico and an AAS in Fashion Design from Parsons School of Design in New York.

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