Cats are very good at hiding pain and discomfort. In the wild, showing weakness could make them vulnerable, and this instinct still exists in domestic cats today. Because of this, many cat illnesses go unnoticed until they become serious. As a cat owner, it is important to recognize early warning signs that something is wrong. Knowing the signs your cat is sick can help you act quickly and get veterinary care before the condition worsens. Small changes in behavior, eating habits, or appearance can be important clues about your cat’s health. Ignoring these signs may lead to serious health problems that could have been prevented with early treatment.
This article highlights the key signs of illness in cats that you should never ignore. By learning what to watch for, you can protect your cat’s health, reduce suffering, and ensure a longer, happier life for your pet.
Changes to Drinking or Eating Patterns
Changes in your cat’s eating or drinking habits are often one of the earliest signs that something is wrong. Cats are creatures of routine, so even small changes can indicate illness and should never be ignored.
Loss of Appetite
A noticeable decrease in how much or how often your cat eats can signal a health problem.
Cats may stop eating due to dental pain, digestive issues, infections, or stress. Even skipping meals for more than 24 hours can be dangerous, especially for adult cats.
Example:
If your cat usually finishes meals quickly but suddenly leaves most of the food untouched for two days, this could be a sign of illness rather than picky eating.
Sudden Increase in Appetite
Eating more than usual can also be a warning sign.
An increased appetite may be linked to conditions such as diabetes, hyperthyroidism, or parasites. Your cat may eat frequently but still lose weight.
Example:
If your cat constantly begs for food but appears thinner than usual, it is important to consult a veterinarian.
Drinking More Water Than Usual
An increase in water intake is a common symptom of several serious health issues.
Practical Explanation:
Excessive thirst may indicate kidney disease, diabetes, or urinary tract infections. Cats often hide symptoms, making this change easy to overlook.
Example:
If you notice your cat visiting the water bowl repeatedly or emptying it faster than normal, this could signal an underlying problem.
Drinking Less or Avoiding Water
A decrease in water consumption can be just as concerning as drinking too much.
Cats that drink less may be experiencing mouth pain, dehydration, or digestive discomfort. Reduced water intake can quickly lead to serious complications.
Example:
If your cat normally drinks regularly but suddenly avoids the water bowl, it may be due to dental pain or illness.
Difficulty Eating or Chewing
Struggling to eat can point to problems in the mouth or throat.
Dental disease, broken teeth, mouth ulcers, or infections can make chewing painful, causing your cat to eat slowly or drop food.
Example:
If your cat approaches the food bowl but walks away after a few bites, or chews only on one side, this may indicate dental issues.
Vomiting After Eating or Drinking
Frequent vomiting related to meals should never be ignored.
Occasional hairballs are normal, but repeated vomiting after eating or drinking can suggest gastrointestinal problems or poisoning.
Example:
If your cat vomits shortly after every meal for several days, this is a clear sign that veterinary attention is needed.
When to See a Veterinarian
If changes in eating or drinking last longer than 24 hours, or are combined with weight loss, lethargy, vomiting, or behavior changes, seek veterinary care immediately. Early detection can prevent serious health complications.
The absence of energy or tiredness
A noticeable drop in your cat’s energy level is one of the most important warning signs of illness. Cats are naturally curious and alert animals, so ongoing tiredness or lack of activity should never be ignored.
What Does Lack of Energy in Cats Look Like?
Healthy cats usually show interest in their surroundings, playtime, and interaction. When a cat becomes unusually inactive, it may indicate an underlying health issue.
Lack of energy may appear as excessive sleeping, reluctance to move, or avoiding activities your cat normally enjoys.
Example:
If your cat used to run toward food time but now stays lying down or moves slowly, this change in behavior could signal illness.
Common Causes of Tiredness in Cats
Several medical and emotional conditions can cause fatigue in cats.
Low energy may be linked to infections, fever, pain, anemia, dehydration, parasites, or chronic diseases. Stress and anxiety can also affect a cat’s energy levels.
Example:
A cat with a urinary tract infection may appear tired because of discomfort and pain, even if no other symptoms are immediately visible.
How to Differentiate Normal Rest from Concerning Fatigue
Cats sleep a lot naturally, but there is a difference between normal rest and abnormal lethargy.
Normal sleep involves relaxed rest with normal appetite and alert moments. Concerning fatigue is constant, deep lethargy combined with behavioral changes.
Example:
A healthy cat may nap during the day but still play at night. A sick cat may sleep constantly and show little interest in food or interaction.
Behavioral Changes Linked to Low Energy
Lack of energy is often accompanied by other behavioral changes.
A tired or sick cat may hide, avoid people, stop grooming, or react irritably when touched.
Example:
If your normally affectionate cat suddenly hides under furniture and avoids being handled, low energy may be linked to discomfort or illness.
Why This Symptom Should Never Be Ignored
Prolonged tiredness can be an early sign of serious health conditions.
Cats instinctively hide weakness, so visible fatigue often means the illness has progressed.
Example:
Conditions such as kidney disease or diabetes often first appear as unexplained lethargy before more severe symptoms develop.
When to Seek Veterinary Help
Knowing when to act can protect your cat’s health.
If your cat’s low energy lasts more than 24–48 hours or appears suddenly and severely, veterinary attention is recommended.
Example:
A cat that refuses to move, stops eating, and appears weak should be taken to the vet immediately.
Diarrhea or vomiting
Diarrhea or vomiting in cats is a common warning sign that should never be ignored, especially when it happens frequently or lasts more than a day. While an occasional upset stomach may not be serious, repeated episodes can indicate underlying health problems.
What Diarrhea and Vomiting Look Like in Cats
Understanding the signs helps you act quickly.
Practical Explanation:
- Diarrhea appears as loose, watery, or unusually frequent stools.
- Vomiting may include undigested food, foam, bile, or hairballs.
Example:
If your cat normally uses the litter box once or twice a day but suddenly produces watery stool multiple times, this change signals digestive trouble.
Common Causes of Diarrhea or Vomiting
These symptoms can result from mild to serious conditions.
Possible causes include dietary changes, food allergies, spoiled food, parasites, infections, stress, poisoning, or internal diseases such as kidney or liver problems.
Example:
If you recently switched your cat’s food and vomiting starts shortly afterward, the new diet may be upsetting their stomach.
When Diarrhea or Vomiting Becomes Dangerous
Some situations require immediate veterinary attention.
Practical Explanation:
Diarrhea or vomiting is considered serious if it:
- Lasts more than 24 hours
- Contains blood
- Is accompanied by lethargy, fever, or loss of appetite
- Occurs in kittens or senior cats
Example:
A kitten that vomits repeatedly and refuses food can become dehydrated very quickly, making this an emergency situation.
Signs of Dehydration to Watch For
Fluid loss is a major risk with diarrhea and vomiting.
Practical Explanation:
Symptoms of dehydration include dry gums, sunken eyes, weakness, and reduced skin elasticity.
Example:
If you gently lift the skin on your cat’s neck and it does not return quickly to normal, dehydration may already be present.
What You Should Do as a Cat Owner
Prompt action can prevent complications.
Practical Explanation:
- Monitor frequency and duration of symptoms
- Ensure access to fresh water
- Avoid giving human medications
- Contact a veterinarian if symptoms persist or worsen
Example:
If your cat vomits once but behaves normally afterward, observation may be enough. However, continued vomiting means it’s time to call the vet.
Unexpected Weight Gain or Loss
Sudden or unexplained changes in your cat’s weight are one of the most important warning signs of illness. Cats are naturally good at hiding discomfort, so noticeable weight gain or loss often means something is wrong internally and should never be ignored.
What Is Considered “Unexpected” Weight Change?
Unexpected weight change means your cat gains or loses weight without any change in diet, activity level, or lifestyle.
Key Indicators:
- Visible ribs, spine, or hip bones
- A rounder belly or thicker body without increased feeding
- Clothes or collars fitting differently
- Changes noticed over a short period of time
Even small weight changes can be significant in cats due to their smaller body size.
Causes of Sudden Weight Loss in Cats
Unexplained weight loss often signals an underlying health issue.
Common Causes Include:
- Digestive problems or parasites
- Dental disease causing pain while eating
- Kidney disease or diabetes
- Thyroid disorders (hyperthyroidism)
- Cancer or chronic infections
Example:
If your cat eats regularly but continues to lose weight, it may be suffering from hyperthyroidism, a common condition in older cats that increases metabolism and causes rapid weight loss.
Causes of unexpected weight gain in cats
Weight gain can also indicate illness, not just overeating.
Common Causes Include:
- Hormonal imbalances
- Fluid retention due to heart or liver disease
- Reduced activity caused by pain or arthritis
- Side effects of medication
Example:
A cat with heart disease may gain weight quickly due to fluid buildup in the abdomen, making the cat appear bloated rather than simply overweight.
Why Weight Changes Are a Serious Warning Sign
Weight changes often reflect internal problems that may not show obvious symptoms at first.
Why It Matters:
- Early detection improves treatment success
- Prolonged weight loss weakens the immune system
- Excess weight may hide fluid retention or organ issues
Ignoring weight changes can allow a treatable condition to become life-threatening.
What You Should Do as a Cat Owner
Taking early action can protect your cat’s health.
Recommended Steps:
- Weigh your cat regularly at home or during vet visits
- Monitor eating habits and activity levels
- Schedule a veterinary checkup if weight changes occur
- Never change diet drastically without professional advice
Example:
If you notice your cat has lost noticeable weight over a month despite normal eating, a vet visit can help identify issues like kidney disease before it progresses.
Changes to Toilet Box Practices
A cat’s litter box habits are one of the clearest indicators of their health. Any sudden or unusual change in how your cat uses the toilet box should never be ignored, as it may signal an underlying medical or emotional issue.
Using the Litter Box More or Less Often
Changes in how frequently your cat uses the toilet box can indicate health problems.
Explanation:
If your cat urinates more often than usual, it may point to kidney disease, diabetes, or urinary tract infections. Less frequent urination may indicate dehydration or urinary blockage, which is a medical emergency.
Example:
A cat that normally urinates twice a day but suddenly goes every hour could be experiencing a urinary tract infection and needs veterinary attention.
Straining or Crying While Using the Toilet Box
Struggling or vocalizing during toilet use is a serious warning sign.
Explanation:
Pain, inflammation, or blockages in the urinary tract or intestines can cause discomfort while urinating or defecating.
Example:
If your cat squats in the litter box, cries, and produces little or no urine, this could indicate a urinary blockage and requires immediate vet care.
Accidents Outside the Litter Box
When a well-trained cat starts avoiding the litter box, it often signals a problem.
Explanation:
Cats may associate the litter box with pain and choose other locations. Stress, anxiety, or mobility issues can also contribute.
Example:
A cat with arthritis may avoid climbing into a high-sided litter box and begin urinating on the floor instead.
Changes in Stool or Urine Appearance
The appearance of waste can reveal important health clues.
Explanation:
Diarrhea, constipation, blood, mucus, or unusually strong odors may point to digestive issues, infections, or internal bleeding.
Example:
Finding blood in your cat’s stool or urine is never normal and should prompt an immediate vet visit.
Excessive Digging or Avoiding the Litter Box
Behavioral changes around the toilet box can reflect discomfort or illness.
Explanation:
Cats may dig excessively due to irritation or avoid the litter box completely if they associate it with pain.
Example:
A cat that repeatedly enters the litter box but leaves without using it may be experiencing urinary discomfort.
Sudden Changes Without Litter or Location Changes
If no changes have been made to the litter type or box placement, health issues are more likely.
Explanation:
Behavioral changes caused by illness usually appear without any environmental triggers.
Example:
If your cat has used the same litter for years but suddenly stops using the box, illness should be ruled out before assuming behavioral issues.
Why This Sign Should Never Be Ignored
Toilet box changes are often the earliest signs of serious conditions such as urinary tract disease, kidney problems, or digestive disorders. Early detection can prevent complications and save your cat’s life.
What You Should Do
- Monitor litter box habits daily
- Note frequency, appearance, and behavior
- Contact your veterinarian immediately if changes persist for more than 24 hours
Modifications to Grooming Practices
Changes in your cat’s grooming habits are often one of the earliest and most noticeable signs of illness. Cats are naturally clean animals, so any modification whether grooming too much or too little should never be ignored.
Reduced Grooming or Neglecting Self-Care
When a cat stops grooming regularly, it may indicate physical pain, fatigue, or an underlying health problem.
Practical Explanation:
Sick cats often lack the energy or comfort needed to maintain their usual grooming routine. Conditions such as arthritis, fever, dental pain, or infections can make grooming uncomfortable.
Example:
If your cat’s coat becomes greasy, tangled, or develops mats—especially in hard-to-reach areas—it may be a sign that your cat is feeling unwell or in pain.
Excessive Grooming or Over-Licking
Some cats respond to discomfort or stress by grooming excessively.
Practical Explanation:
Over-grooming can be a response to skin irritation, allergies, parasites, pain, or emotional stress. Constant licking may damage the skin and cause hair loss.
Example:
If your cat repeatedly licks one spot until the fur thins or bald patches appear, it could signal an underlying issue that requires veterinary attention.
Changes in Coat Appearance
A healthy cat’s coat is usually smooth and shiny. Illness often affects coat quality.
Practical Explanation:
Nutritional deficiencies, dehydration, digestive problems, or chronic disease can cause the coat to look dull or unkempt.
Example:
If your cat’s fur suddenly looks rough, flaky, or lifeless despite no change in diet or environment, it may indicate internal health problems.
Grooming Only Certain Areas
Selective grooming focusing too much on one area while ignoring others—can be a warning sign.
Practical Explanation:
Cats may lick areas that feel painful or irritated, such as joints, the abdomen, or near wounds.
Example:
A cat that constantly licks its belly or paws may be experiencing pain, allergies, or urinary discomfort.
Avoidance of Grooming-Related Activities
Some cats become sensitive to touch when sick.
Practical Explanation:
If grooming causes discomfort, your cat may avoid being brushed or become irritated when touched.
Example:
A normally affectionate cat that hisses or pulls away during brushing could be signaling pain or illness.
Why Grooming Changes Should Never Be Ignored
Grooming habits reflect a cat’s overall health and emotional state. Even subtle changes can be early warning signs of serious conditions. Monitoring these changes allows for early diagnosis and timely treatment.
When to See a Veterinarian
If grooming modifications persist for more than a few days or are accompanied by other symptoms such as lethargy, appetite loss, or behavioral changes, consult a veterinarian immediately.
Continuous Sneezing or Coughing
Occasional sneezing in cats can be harmless, but continuous sneezing or coughing is a warning sign that should never be ignored. Persistent respiratory symptoms often indicate an underlying health problem that requires attention.
What Is Considered Continuous Sneezing or Coughing?
Sneezing or coughing becomes concerning when it happens frequently over several days or worsens over time.
Practical Explanation:
If your cat sneezes or coughs multiple times a day, every day, or shows no improvement after 2–3 days, it is considered continuous.
Example:
A cat that sneezes once after smelling dust is normal. However, a cat that sneezes repeatedly throughout the day for several days may be experiencing a health issue.
Common Causes of Continuous Sneezing or Coughing
Several conditions can cause persistent respiratory symptoms in cats.
Practical Explanation:
The most common causes include:
- Upper respiratory infections
- Allergies
- Asthma
- Foreign objects stuck in the nose or throat
- Dental infections spreading to the sinuses
Example:
A cat with a respiratory infection may sneeze constantly and develop watery or thick nasal discharge, while a cat with asthma may cough in short, repeated bursts.
Signs That Make It More Serious
Sneezing or coughing becomes more serious when accompanied by other symptoms.
Practical Explanation:
Watch for:
- Nasal discharge (clear, yellow, or green)
- Watery or swollen eyes
- Loss of appetite
- Lethargy or weakness
- Difficulty breathing
Example:
If your cat is coughing and also refusing food or breathing with an open mouth, this may indicate a severe condition needing urgent care.
Why You Should Never Ignore This Symptom
Cats often hide illness, so visible symptoms usually mean the problem has progressed.
Practical Explanation:
Ignoring continuous sneezing or coughing can allow infections or respiratory diseases to worsen, making treatment more difficult and costly.
Example:
A mild untreated respiratory infection can turn into pneumonia if left unattended, especially in kittens or older cats.
When to Contact a Veterinarian
Timely veterinary care can prevent serious complications.
Practical Explanation:
You should contact a veterinarian if:
- Sneezing or coughing lasts more than 2–3 days
- Symptoms worsen instead of improving
- Your cat struggles to breathe or becomes unusually quiet
Example:
A cat coughing every night or wheezing after minimal activity should be examined immediately to rule out asthma or lung disease.
How Early Treatment Helps Your Cat
Early diagnosis leads to faster recovery and less discomfort.
Practical Explanation:
Depending on the cause, treatment may include antibiotics, allergy medication, inhalers, or supportive care.
Example:
A cat diagnosed early with an upper respiratory infection often recovers within a week with proper medication and rest.
Modifications in Behavior
Behavioral changes are often one of the earliest and most noticeable signs that your cat may be unwell. Cats are experts at hiding pain or discomfort, so even subtle shifts in their usual behavior should never be ignored.
Increased Hiding or Withdrawal
Healthy cats usually have predictable routines and favorite spots. If your cat suddenly starts hiding more than usual, avoids interaction, or withdraws from family members, it may indicate illness or pain.
Example:
A cat that normally sleeps on the couch or follows you around the house begins spending most of the day under the bed or in dark corners. This can be a sign of stress, infection, or internal pain.
Changes in Activity Level
A noticeable change in how active your cat is can signal a health problem. Both lethargy and unusual restlessness are concerning.
- Lethargy: Sleeping more, moving slowly, or losing interest in play
- Restlessness: Pacing, inability to settle, or appearing uncomfortable
Example:
If your playful cat no longer chases toys or jumps onto furniture, it may be experiencing joint pain, fever, or general weakness.
Altered Social Behavior
Cats have distinct social personalities. A sudden shift—either becoming unusually aggressive or overly clingy can be a sign that something is wrong.
Example:
A friendly cat that suddenly hisses, growls, or avoids being touched may be reacting to pain. On the other hand, a normally independent cat that becomes excessively needy could be seeking comfort due to discomfort or illness.
Unusual Vocalization
Changes in the way your cat vocalizes can also reflect behavioral modifications caused by illness.
Example:
A cat that suddenly meows more than usual, cries at night, or makes low, distressed sounds may be experiencing pain, confusion, or anxiety.
Why This Sign Should Never Be Ignored
Behavioral changes are often your cat’s only way of communicating discomfort or illness. Since cats instinctively hide weakness, any noticeable modification in behavior no matter how minor it seems should be taken seriously and discussed with a veterinarian.
Symptoms of Pain or Uncomforted
Cats are experts at hiding pain. In the wild, showing weakness makes them vulnerable, and that instinct still exists in domestic cats. Because of this, pain or discomfort often appears through subtle behavior and physical changes, not loud cries or obvious limping. Recognizing these signs early can help prevent serious health complications.
Changes in Behavior
One of the first indicators of pain is a noticeable change in your cat’s usual behavior.
- A normally friendly cat may become withdrawn, aggressive, or irritable
- Your cat may hide more often or avoid human interaction
- Reduced interest in play or activities they once enjoyed
Example:
If your cat usually greets you at the door but suddenly hides under the bed and growls when touched, this could indicate pain caused by injury, arthritis, or internal illness.
Changes in Movement or Posture
Pain often affects how a cat moves or holds their body.
- Limping or reluctance to jump or climb
- Stiff movements, especially after resting
- Sitting or lying in unusual positions to avoid pressure on painful areas
Example:
A cat with joint pain may stop jumping onto furniture and instead stay on the floor, even if they previously loved high places.
Excessive Grooming or Lack of Grooming
Cats use grooming to soothe themselves, but changes in grooming habits can signal discomfort.
- Over-grooming one area, causing bald spots or skin irritation
- Completely stopping grooming, leading to a dull or matted coat
Example:
A cat repeatedly licking its abdomen may be experiencing urinary pain or digestive discomfort.
Vocalization Changes
Cats in pain may communicate differently.
- Increased meowing, growling, hissing, or crying
- Low-pitched or unusual sounds, especially when moving or being touched
Example:
If your usually quiet cat begins yowling when picked up, it may be experiencing internal pain or muscle injury.
Changes in Eating and Litter Box Habits
Pain can directly affect appetite and bathroom behavior.
- Eating less or refusing food
- Difficulty using the litter box
- Crying or straining while urinating or defecating
Example:
A cat that sits in the litter box for long periods and cries may be suffering from a urinary tract infection, which is a medical emergency.
Why These Symptoms Should Never Be Ignored
Pain is not a normal part of a cat’s life. Even mild discomfort can be a sign of a serious underlying condition such as infection, injury, dental disease, or organ problems. Early veterinary attention can greatly improve treatment outcomes and reduce your cat’s suffering.
FAQs
How can I tell if my cat is sick if they hide symptoms?
Cats often hide illness, so look for small changes in behavior such as reduced appetite, hiding, aggression, or changes in grooming and litter box habits.
What are the most common signs of illness in cats?
Common warning signs include lethargy, vomiting, diarrhea, weight loss, breathing difficulties, limping, and unusual vocalization.
When should I take my cat to the vet?
You should contact a veterinarian immediately if symptoms last more than 24 hours, worsen suddenly, or include difficulty breathing, inability to eat, or trouble urinating.
Is a change in appetite always a sign of illness?
Not always, but persistent loss of appetite or sudden overeating can indicate health issues such as dental pain, digestive problems, or organ disease.
Why is my cat hiding more than usual?
Increased hiding often means your cat is feeling unwell, stressed, or in pain. It’s one of the most common early signs of illness in cats.
Can changes in litter box habits indicate serious problems?
Yes. Straining, crying, accidents outside the litter box, or changes in urine or stool can signal infections, kidney disease, or blockages.
Conclusion
Pet owners need to be watchful and sensitive because cats are excellent at hiding their discomfort and disease. Small changes in your cat’s food patterns, grooming schedule, energy level, or temperament can be a sign of major health issues. Ignoring these symptoms could make the sickness worse and make treatment more challenging or expensive. Maintaining your cat’s health requires regular medical checkups, a clean living space, a suitable diet, and regular tracking. Trust your senses and get medical help if you think your cat is “not acting normal.” In addition to avoiding your cat from suffering, early care improves your relationship with your valued animal friend.
